Timing Control Research Articles

Use of magnetic sheets in vertical deformation treatment of textile supports of contemporary paintings

The practice developed during a conservation and restoration intervention does not always follow common or traditional standards, whether due to technical limitations, or space constraints related to the size of the works, or by the material requirements that the works themselves can present. In the light of various particularities and needs, research was initiated into the use of harmless and satisfactory methods in the occasional treatment of deformations of the support of contemporary pictorial works, using magnetic sheets. In its use, different valences were evaluated, such as the control in the iteration of the work, the effectiveness and control of humidity and time during the performance of the treatments, and the results obtained. This article will reflect on the process developed with the application of four case studies, presenting the advantages and disadvantages in the use of this method.

A one-step integrated forming and curing process for smart thin-walled fiber metal laminate structures with self-sensing functions

This study proposes and analyzes a novel one-step integrated forming and curing (IFC) process for thin-walled fiber metal laminates (FMLs) structures embedded with fiber Bragg grating (FBG) sensors, and have achieved both high-performance properties and self-sensing functions in the formed structures. A prototype machine and testing setup have been developed to validate the process's feasibility by manufacturing high-performance FMLs flat and curvature parts with effective self-sensing capabilities for real-time manufacturing and in-service monitoring. Numerical models considering curing-induced deformation and heat transfer during manufacturing have also been developed to support the analysis and validation of the self-monitoring capabilities of the intelligent FMLs parts. The results reveal that with proper control of pressure (e.g., 0.6 MPa) and time during forming and curing, high tensile and impact performance of FMLs can be maintained with embedded FBG, with less than a 3% loss. Additionally, the IFC process can effectively lead to an apparent reduction of springback deformation in the formed FMLs (more than 80%). The validation of the self-sensing function during the manufacturing process has been achieved by comparing the strain monitoring results with finite element (FE) simulation results during curing, with a minimum discrepancy of 2.0%. For the in-service self-sensing function, comparison between FE analysis and surface-fixed strain gauges during the compression instability test confirmed the efficacy of FBG sensors, with a minimum discrepancy of 4.3%. The results show that the proposed novel IFC process enables the successful manufacture of smart thin-walled FMLs parts with high shape accuracy and mechanical properties in a single step and holds significant promise for manufacturing self-sensing smart structures in the aerospace and aviation industries.

Design and Application of Real‐Time and High‐Precision Seismic Acquisition Station in Antarctic Region

ABSTRACTIn this study, a polar seismic acquisition station based on the FPGA + ARM architecture was successfully developed. This system can achieve real‐time multifunctional acquisition and transmission of seismic signals and environmental information in the extreme low‐temperature environment of Antarctica at −40°C. The system adopts a modular design, with high‐precision data acquisition encoded by the main controller and uploaded to the host computer in real‐time. Integrated display controls enable real‐time data display and acquisition station location mapping for user interaction. We propose improving data transmission in traditional seismic acquisition stations by adopting a distributed computing model with data segment return. Integrating the first arrival picking algorithm as an IP core will reduce computational demands on the data processing center. This acquisition system features high precision (24‐bit), a wide dynamic range (> 130dB), low noise (0.5 V rms@40dB), and high‐precision timing control (200 ns). It supports real‐time wireless data transmission over 120 channels up to 1 km. The system also implements a self‐storage plus wired and wireless networking solution, allowing flexible networking based on actual needs. Test results indicate that the ice sheet thickness at the acquisition site is approximately 526.49 m, validating the experimental design's effectiveness and providing technical support for subsequent drilling and seismic exploration.

Family caregivers’ administration of medications at the end-of-life in China: a qualitative study

BackgroundEffective medication management is crucial for ensuring timely pain and symptom control at the end of life. Dying in pain is a major concern for patients, yet some find less effective pain control at home. Family caregivers (FCGs) play a vital role in managing pain and symptom control for dying patients. However, the experience of administering medications at home for terminal-stage patients has not been widely recognized or understood. Our study aimed to explore the experiences of FCGs in administering medications to adult dying patients.MethodsWe conducted a directed content analysis of data from 73 semi-structured interviews with FCGs across 19 Chinese provinces from 2021 to 2023. FCGs were recruited through the Voluntary Cooperative Network Research. We asked, “Could you recall the end-of-life care process for the patients?” We aligned the themes with the five issues identified by Wilson et al. (2018): administration, organizational skills, empowerment, relationships, and support.ResultsFCGs in China exhibit concerns about over-engagement and empowerment in medication administration, concealing medication information from the patient, and medication accessibility. FCGs faced significant challenges in accurately identifying and addressing pain and symptoms, determining appropriate dosages, accessing effective medications, and managing the emotional stress associated with potential medication errors. Financial burden, medication regulatory restrictions, geographical inequality, and travel restrictions during COVID impeded patients and FCGs from accessing medication. A culturally specific finding is the use of alternative medicine at the end of life.ConclusionOur findings build upon Wilson et al.‘s framework and extend their insights on empowerment, highlighting the need for policies to support home-based palliative care professionals in training FCGs for effective medication administration.

Sleep disturbances in anorexia nervosa.

Sleep is crucial for physical and psychological health, and disturbances are closely linked to psychiatric disorders, making their management essential for improving treatment outcomes and preventing relapse. Although sleep disturbances are implicated in psychopathology of eating disorders, its role in anorexia nervosa (AN) remains unclear. This review aimed to characterise sleep in AN. A systematic search was conducted in four scientific databases, including papers from inception to 25 May 2024. A machine learning algorithm (ASReview) was utilised to screen titles and abstracts for eligibility. Sleep quantity, architecture, and quality were investigated. Meta-analyses were conducted to investigate the difference between patients with AN and healthy controls (HC) in total sleep time (TST), wake after sleep onset (WASO), sleep onset latency (SOL), sleep efficiency, Sleep Stage 1, 2, slow wave sleep, rapid eye movement (REM) sleep and REM latency. Certainty of evidence was assessed using the GRADE approach. Out of 67 potentially eligible papers, 31 were included in this review, with 15 in the meta-analyses. Statistically significant average mean differences were found for TST (-32.1min [95% CI: -50.9, -13.4]), WASO (19.0min [95% CI: -2.4, 40.3]), and sleep efficiency (-4.4% [95% CI: -7.9, -0.9]). Additionally, Sleep stage 1 was significantly increased (2.4% [95%-CI: 0.05, 4.7]), while REM sleep was reduced (-2.1% [95%-CI: -4.2, -0.02]). Subgroup analysis showed that TST and WASO did not improve significantly after weight restoration. Sleep in patients with AN is impaired, with lower TST and sleep efficiency, higher WASO, more time in stage 1 sleep, and less in REM. Weight restoration alone may not improve sleep. While more research is needed, substantial accompanying sleep disturbances in AN justifies addressing these in current treatment practice, also because of the chronic character of AN and importance of sleep for long term (mental) health.

Water-assisted preparation of Ni/La(OH)3 catalyst for efficient catalytic C-O bond hydrogenolysis of tetrahydrofuran-dimethanol

Due to easy dehydration of La(OH)3 to LaOOH by thermal treatment, it is challenging to prepare highly efficient Ni/La(OH)3 catalyst for hydrogenolysis reactions. Herein, Ni/La(OH)3 (Ni/La-2) catalyst is prepared by thermal reduction of NiO/La(OH)3 in hydrogen flow with vaporized water, while La(OH)3 is partially dehydrated to LaOOH without water vapor affording Ni/(La(OH)3 + LaOOH) (Ni/La-1). Ni/La-2 displays 93 % and 3 % yields of 1,2,6-hexanetriol (HTO) and 1,6-hexanediol (HDO) respectively towards C-O hydrogenolysis of tetrahydrofuran-dimethanol (THFDM) in batch reactor and high stability (200 h) in fixed-bed reactor, which is the best among the reported catalysts to the best of our knowledge. Ni/La-2 possesses pure La(OH)3 as support, enhanced dispersion of Ni species and abundant Niδ+-O-La interfaces in comparison to Ni/La-1, which results in the exceptional catalytic performances in C-O hydrogenolysis of THFDM. A fine control of reaction temperature and time is required to optimize the yields HTO and HDO in hydrogenolysis of THFDM over Ni/La-2. The water-assisted preparation method provides a new perspective for the preparation of La(OH)3 supported metal catalysts.

Clean-up of wastewater discharged from zinc industry through application of zeolite 4A produced from a waste contaminated by lubricant oil components

The zeolite 4 A powders were sustainably derived from clay-based waste contaminated with the spent lubricant oil. Then, the products were used to treat the wastewater discharged from a local zinc industry. The main challenge is removal of toxic organic components from the waste and conversion of obtained precursor to the zeolite structure, simultaneously. The variation in crystallinity was studied as a function of composition, fusion temperature, aging, and recrystallization times. The zinc adsorption was found to be markedly dependent not only on sodium carbonate/waste ratio but also on aluminum hydroxide content. However, pronounced adsorption was observed over the particles fabricated through the fusion at 900 °C. The relative crystallinity, ∼32 %, is crucial for the effective immobilization of heavy metal ions like Cd2+, Ni2+, and Zn2+ from the wastewater. This level of crystallinity is achievable with the control of aging and recrystallization times, both in 3 h. The maximal zinc adsorption capacity, ∼143 mg g−1, was obtained for the particles with large pores, 48 nm, facilitating the ion diffusion into the adsorbent. On the other hand, the appropriate electrical charge surface expressed based on zeta potential, −43 mV, provided a proper condition for the electrostatic adsorption.

Enantiomer-Specific Pumping of Chiral Molecules.

Enantiomer-specific state transfer (ESST), which involves transferring enantiomers with different handedness of a chiral molecule into different-energy internal states, is a challenging yet significant task. Previous ESST methods are based on dynamic processes and thus require the preparation of initial states and precise control of microwave operation times. We propose a novel ESST approach, called enantiomer-specific pumping (ESP), which is based on a dissipative process and thereby eliminates the need for these two technical requirements. This approach utilizes a special microwave-induced dark state that appears exclusively for the enantiomer with a specific handedness. Specifically, in ESP, the enantiomer lacking the dark state can be pumped out of the subspace of relevant internal states, while the enantiomer with the dark state maintains a finite probability within this subspace, offering high efficiency in ESST. Notably, ESP facilitates enantiodetection without the need for enantiopure samples as reference.

Dual-Approach Co-expression Analysis Framework (D-CAF) Enables Identification of Novel Circadian Regulation From Multi-Omic Timeseries Data.

The circadian clock is a central driver of many biological and behavioral processes, regulating the levels of many genes and proteins, termed clock controlled genes and proteins (CCGs/CCPs), to impart biological timing at the molecular level. While transcriptomic and proteomic data has been analyzed to find potential CCGs and CCPs, multi-omic modeling of circadian data, which has the potential to enhance the understanding of circadian control of biological timing, remains relatively rare due to several methodological hurdles. To address this gap, a Dual-approach Co-expression Analysis Framework (D-CAF) was created to perform perturbation-robust co-expression analysis on time-series measurements of both transcripts and proteins. Applying this D-CAF framework to previously gathered transcriptomic and proteomic data from mouse macrophages gathered over circadian time, we identified small, highly significant clusters of oscillating transcripts and proteins in the unweighted similarity matrices and larger, less significant clusters of of oscillating transcripts and proteins using the weighted similarity network. Functional enrichment analysis of these clusters identified novel immunological response pathways that appear to be under circadian control. Overall, our findings suggest that D-CAF is a tool that can be used by the circadian community to integrate multi-omic circadian data to improve our understanding of the mechanisms of circadian regulation of molecular processes.

8428 Rare Variants in the MECP2 Gene in Two Boys with Central Precocious Puberty

Abstract Disclosure: A.P. Canton: None. J.B. Mebarak: None. M. Magnuson: None. S. Roberts: None. N. Mauras: None. M. Benson: None. S. Witchel: None. R.S. Carroll: None. A. Latronico: None. U.B. Kaiser: None. A. Abreu: None. Introduction: Central precocious puberty (CPP) occurs more frequently in girls and is usually labelled as idiopathic; however, in boys organic causes are more frequent. Identification of imprinted genes causing CPP have revealed epigenetic mechanisms underlying puberty. MECP2, an X-linked gene, encodes a methylated DNA reader protein with a role in gene transcription. MECP2 loss-of-function mutations usually cause Rett syndrome, a severe neurodevelopmental disorder that may be associated with early pubertal development. Recently, rare variants in MECP2 have been recognized in girls with sporadic CPP with or without mild neurodevelopmental disorders. In our cohort of 78 patients with idiopathic CPP, no MECP2 mutations were identified in 73 girls. In this study, five boys with CPP were evaluated for potential MECP2 sequence variants. Methods and Results: Five boys with CPP were screened for MECP2 sequence variants using Sanger sequencing. At the time of CPP diagnosis, they had median (interquartile range) chronological age 9.2 yr (4.3), bone age advancement 2.1 yr (3.5), height SDS 2.3 (1.5), basal LH levels 1.6 IU/L (0.9), and testosterone levels 370 ng/dL (570). Organic causes of CPP were excluded. No MKRN3 or DLK1 mutations were identified. Familial segregation analysis was performed when appropriate. We identified a hemizygous MECP2 variant in a boy (Patient 1) who presented at age 2.7 yr with sporadic CPP. In addition, he had speech delay and behavioral changes, defined as autism spectrum disorder by neuropsychological assessment. He harbored an extremely rare (gnomAD AF=0.000004956) missense variant (p.Val312Ile) in exon 3 of MECP2, encoding the transcriptional repression domain, critical for protein function. The p.Val312Ile mutation was classified as likely pathogenic (ACMG criteria) with a potential association with the phenotype. Another hemizygous MECP2 variant was identified in a boy (Patient 2) who presented at age 8.0 yr with sporadic CPP; he had no neurodevelopmental conditions. He harbored a rare (gnomAD AF=0.00008) missense variant (p.Arg366Cys) in exon 3, encoding the C-terminal domain, classified as a variant of uncertain significance (ACMG criteria). Familial segregation analysis revealed that both boys inherited the MECP2 variants from their unaffected mothers, consistent with a pattern of clinical variability described in women with defects in X-linked genes.Conclusions: We identified rare MECP2 variants in two boys with sporadic CPP without classic features of Rett syndrome, expanding the phenotype of patients with MECP2 mutations, as described in girls. The MECP2 p.Val312Ile variant was likely pathogenic, whereas the functional significance of the p.Arg366Cys variant in still indeterminate. These findings provide additional evidence for a role of MECP2, an epigenetic factor, in the hypothalamic control of pubertal timing. Presentation: 6/1/2024

Genetic analysis of selection bias in a natural experiment: Investigating in-utero famine effects on elevated body mass index in the Dutch Hunger Winter Families Study.

Natural-experiment designs that compare survivors of in-utero famine exposure to unaffected controls suggest that in-utero undernutrition predisposes to development of obesity. However, birth rates drop dramatically during famines. Selection bias could arise if factors that contribute to obesity also protect fertility and/or fetal survival under famine conditions. We investigated this hypothesis using genetic analysis of a famine-exposed birth cohort. We genotyped participants in the Dutch Hunger Winter Families Study (DHWFS, N=950; 45% male), of whom 51% were exposed to the 1944-1945 Dutch Famine during gestation and 49% were their unexposed same-sex siblings or "time controls" born before or after the famine in the same hospitals. We computed body-mass index (BMI) polygenic indices (PGIs) in DHWFS participants and compared BMI PGIs between famine-exposed and control groups. Participants with higher polygenic risk had higher BMIs (Pearson r=0.42, p<0.001). However, differences between BMI PGIs of famine-exposed participants and controls were small and not statistically different from zero across specifications (Cohen's d=0.10, p>0.092). Our findings did not indicate selection bias, supporting the validity of the natural-experiment design within DHWFS. In summary, our study outlines a novel approach to explore the presence of selection bias in famine and other natural experiment studies.

Manipulating the d-band center of bimetallic molybdenum vanadate for high performance aqueous zinc-ion battery

Vanadium-based oxides have good application prospects in aqueous zinc ion batteries (AZIBs) due to their structures suitable for zinc ion extraction and intercalation. However, their poor conductivity limits their further development. The d-band center plays a key role in promoting adsorption of ions, which promotes the development of electrode materials. Here, a series of MoV2O8 compounds with oxygen defect (Od-MoV2O8) were synthesized by a simple hydrothermal process and a subsequent vacuum calcination process through strict control of the deoxidation time. Theoretical calculations reveal that the abundant oxygen vacancies in MoV2O8 effectively regulate the d-band center of the zinc ion adsorption site. This precise control of the d-band center enhances the zinc ion adsorption energy of MoV2O8, lowers the migration energy barrier for zinc ions, and ultimately significantly boosts zinc storage performance. The specific capacity is as high as 282.4 mAh/g after 100 cycles at 0.1 A/g, and it also shows excellent performance and outstanding cycle life. In addition, the maximum energy density of Od-MVO-0.5 (MoV2O8 sample deoxidized for 0.5 h) is 343.3 Wh kg−1. Importantly, the mechanism of Zn2+ storage in Od-MoV2O8 was revealed by the combination of in situ and ex situ characterization techniques.

Statistically sound identification of compounds by low-resolution GC-MS: Identification of tear agents in tear gas sprays

Gas-chromatography hyphenated with low-resolution mass spectrometry is a very flexible tool for the cost-effective identification and quantification of volatile compounds in complex matrices. In some analytical fields, criteria for the agreement between retention time and mass spectra of the analyte in calibrators and samples are defined based on the general understanding of the performance of these parameters. However, since this harmonization is not based on experimental performance observed for specific GC-MS conditions and analyte it leads to false identifications. This research proposes a novel and robust tool for defining statistically sound criteria for the identification of compounds by GC-MS and LC-MS using experimental data. The Monte Carlo Method (MCM) simulation of the correlated abundance of characteristic ions of analyte mass spectrum allows simulating the abundance ratio difference of the analyte in a calibrator and sample used for statistically sound identifications. The Cholesky decomposition of the covariance matrix of ion abundances for MCM simulations allows the reliable use of many ion abundance ratios in identifications. The developed methodology was implemented in a user-friendly Excel spreadsheet and applied to the identification of tear gas agents in tear gas sprays. Criteria defined by SANTE for identifying pesticide residues in foodstuffs were compared with the developed tool. The cross-validation of computational and SANTE tools allowed concluding that the statistical control of retention time and mass spectra performs according to the defined confidence level. On the other hand, the SANTE criteria can produce up to 92% false identifications for being too strict considering signal dispersion.

A Bibliometric Analysis of the Errors and Mistakes in the Medical Laboratory

Abstract Background: The increasing number/varieties of tests and rising demands are reasons for the increasing challenges to laboratory professionals, such as increasing workloads, maintaining turnaround time, and quality improvement. Furthermore, the laboratory faces many occupational hazards due to negligence or lack of knowledge regarding biosafety guidelines among the laboratory professionals. A laboratory involves mechanical, chemical, biological, and environmental components of activities, and errors/mistakes/ignorance in any of these disciplines create hazards and risks to people working inside the laboratory. Objective: We aimed to identify the types of errors, accidents, and ignorance in medical/clinical laboratories that have been published or presented worldwide. Materials and Methods: We performed a bibliometric analysis to search and analyze those studies which are published in different journals as articles or reviews, or published as books or chapters, and even, those presented as conference papers and short surveys. Results: The bibliometric analysis shows the pre-analytical phase as the most vulnerable to errors due to human errors and other activities outside the laboratory, which are beyond the control and preview of laboratories many times. A few studies suggest an increase in several tests and a lack of awareness among physicians while ordering the test as one of the reasons for the poor efficiency of laboratory services. Similarly, ignorance of the safety measures leads to occupational hazards among laboratory professionals. Conclusion: The study recommends focusing on the pre-analytical phase and providing awareness to clinicians about the tests conducted by the respective laboratories. This study also highlights that errors in the laboratory should be published for future records and learning.

Beyond the biting - limited impact of explicit mosquito dynamics in dengue models

Mathematical models play a crucial role in assisting public health authorities in timely disease control decision-making. For vector-borne diseases, integrating host and vector dynamics into models can be highly complex, particularly due to limited data availability, making system validation challenging. In this study, two compartmental models akin to the SIR type were developed to characterize vector-borne infectious disease dynamics. Motivated by dengue fever epidemiology, the models varied in their treatment of vector dynamics, one with implicit vector dynamics and the other explicitly modeling mosquito-host contact. Both considered temporary immunity after primary infection and disease enhancement in secondary infection, analogous to the temporary cross-immunity and the Antibody-dependent enhancement biological processes observed in dengue epidemiology. Qualitative analysis using bifurcation theory and numerical experiments revealed that the immunity period and disease enhancement outweighed the impact of explicit vector dynamics. Both models demonstrated similar bifurcation structures, indicating that explicit vector dynamics are only justified when assessing the effects of vector control methods. Otherwise, the extra equations are irrelevant, as both systems display similar dynamics scenarios. The study underscores the importance of using simple models for mathematical analysis, initiating crucial discussions among the modeling community in vector-borne diseases.

AI-powered precursor quantification in atmospheric pressure plasma jet thin film deposition via optical emission spectroscopy

Abstract This study explores the feasibility of using Optical Emission Spectroscopy (OES) for in situ monitoring of Atmospheric Pressure Plasma Jet systems in the deposition of thin films. We identify process parameters to control film properties by machine learning for data analysis. In experiments, the depth of the carrier gas inlet pipe (pipe depth) is a crucial controllable variable that directly affects the amount of precursor, influencing the film’s thickness, sheet resistance, and resistivity. We collected 96 000 spectra while preparing 12 film samples, subsequently measured the properties of the samples, and analyzed the spectral data using Principal Component Analysis (PCA) and seven supervised machine learning models. A high correlation was found between spectral features and film thickness. We divided the spectral data in a single process based on processing time into the first third (F-third) and the last third (L-third). Using the F-third data, the PCA plot clearly indicated a significant difference between the two pipe depths, achieving a mean recognition accuracy of 95.1% with machine learning models. In contrast, using the L-third data, the PCA plot showed a high degree of overlap between the two pipe depths, resulting in a considerable decline in recognition performance. Overall, it is challenging to distinguish the spectra visually due to variations in precursor amounts and dynamic fluctuations in the OES signals, even after averaging. Nonetheless, through the successful application of machine learning, we demonstrated an effective spectral recognition system for monitoring pipe depth, which aids in the timely control of film properties.

Alternative Balance between Transcriptional and Epigenetic Regulation during Developmental Proliferation of Human Cranial Neural Crest Cells.

Cranial neural crest cells are implicated in multiple transcriptional events at the different stages of differentiation during development. The alteration of some transcription factors expressed during neural crest development, like PAX7, could be implicated in the etiology of face malformation in murine models. Epigenetic regulation has been shown to be an important mechanistic actor in the control of timing and the level of gene expression at different stages of neural crest development. During this work, we investigated the interconnection between epigenetics and transcription factors across a diversity of human development cranial neural crest cells. Across a diversity of neural cells from human developing cranial tissues, in accordance with their proliferation stage, an alternative balance of regulation between transcription factors and epigenetic factors was identified.

Barley yellow dwarf virus in winter barley: Control in light of resistance issues and loss of neonicotinoid insecticides

AbstractBarley yellow dwarf virus (BYDV) is the most widespread viral disease of cereal crops vectored by aphids, causing stunting of the crop and significant yield loss. Management recommendations for autumn sown cereals has centred on the timely control of aphid vectors, particularly their management before the crop has reached Growth Stage 31 (stem elongation). In recent years two separate but related issues have emerged, (i) the detection of pyrethroid resistance in a single Sitobion avenae SA3 clone and (ii) the withdrawal of neonicotinoid insecticide seed dressing; widely used to manage aphids in the early development of cereal crops. A series of replicated field studies were conducted from 2016 to 2019 to ascertain if the pyrethroid insecticide is still effective in light of the SA3 clones' presence in aphid populations and if withdrawal of neonicotinoid seed dressings has negatively affected aphid management. Both disease levels and yields confirmed that the neonicotinoid, clothianidin, applied as a seed treatment significantly contributed to the management of BYDV in the different trials investigated. Results of this study demonstrate application of a foliar (lambda‐cyhalothrin or a sulfoxaflor) insecticide has a significant positive impact on yield. Foliar pyrethroid insecticides were as effective in protecting yield from BYDV as the neonicotinoid seed treatments. In the absence of neonicotinoid seed dressing, alternative insecticides still offer protection for winter barley crops against the aphid vectors of BYDV and associated yield loss. Furthermore, the presence of a pyrethroid resistant Sitobion avenae SA3 clone had no observable impact on field efficacy of the pyrethroid insecticide, lambda‐cyhalothrin in these trials. However, this needs continuous monitoring because of potential further increases in resistance levels or emergence of additional resistance mechanisms, which could render pyrethroid insecticides ineffective.

Numerical Simulation and Response Surface Analysis of Esterification of Monobutyl Chlorophosphate with n-Butanol in a Microchannel Reactor

Microreactors are essential for microchemical reactions owing to their high mass transfer efficiency, precise control of reaction time, easy amplification, and good safety performance. These characteristics provide several advantages, including shortened reaction times and enhanced chemical reaction conversion rates, rendering microreactors particularly significant in chemical production. In this study, a finite-rate model was developed for the esterification of monobutyl chlorophosphate (MCP) and n-butanol in a microchannel reactor. This study investigates the impact of the microchannel’s length-to-diameter ratio, the mass ratio of n-butanol to MCP at the inlet, and the inlet flow ratio on the entire reaction system through numerical simulations. The findings indicate that increasing the length-to-diameter ratio and reducing the inlet flow rate effectively prolongs the residence time of materials in the microreactor, thereby enhancing the conversion rate of the reactants. Optimal results are achieved with a moderate n-butanol/MCP mass ratio, which facilitates MCP transformation. Moreover, this study employs response surface analysis to investigate the influence of independent factors, such as the microchannel’s length-to-diameter ratio, component ratio, and inlet velocity ratio, on MCP conversion rates. A prediction formula with conversion rate as the dependent variable and microchannel length-to-diameter ratio, component ratio, and inlet velocity ratio as independent variables was established.

Oxidation-induced graded bandgap narrowing in Two-dimensional tin sulfide for high-sensitivity broadband photodetection

Two-dimensional (2D) layered group-IV monochalcogenides with large surface-to-volume ratio and high surface activity make that their structural and optoelectronic properties are sensitive to air oxidation. Here, we report the utilization of oxidation-induced gradient doping to modulate electronic structures and optoelectronic properties of 2D group-IV monochalcogenides by using SnS nanoplates grown by physical vapor deposition as a model system. By a precise control of oxidation time and temperature, the structural transition from SnS to SnSOx could be driven by the layer-by-layer oxygen doping and intercalation. The resulting SnSOx with a graded narrowing bandgap exhibits the enhanced optical absorption and photocurrent, leading to the fabricated SnSOx photodetector with remarkable photoresponsivity and fast response speed (<64 μs) at a broadband spectrum range of 520–1550 nm. The peak responsivity (7294 A/W) and detectivity (9.54 × 109 Jones) of SnSOx device are at least two orders of magnitude larger than those of SnS photodetector. Moreover, its photodetection performance can be competed with state-of-the-art of 2D materials-based photodetectors. This work suggests that the air oxidation could be utilized as an efficient strategy to engineer the electronic and optical properties of SnS and other 2D group-IV monochalcogenides for the development of high-performance broadband photodetectors.