Typical Profile Research Articles

Lithium (Poly)sulfide Phase Conversion in Working Lithium–Sulfur Batteries: The Insight from the Equilibrium Potential Model

The commercialization of lithium–sulfur (Li–S) batteries is currently hindered by the electrochemical instability and capacity loss, due to the ultracomplex phase conversion of lithium polysulfides (LPSs) and lithium sulfide (Li2S). Revealing the mechanism is critical to rational regulation of the cathode reaction process so as to improve the cycling stability and capacity retention. Herein, we develop an equilibrium potential model to reveal the two conversion pathways under different electrolyte/sulfur ratios of working Li–S batteries. The model predicts that the supersaturation of Li2S and the precipitation of LPSs are responsible for the potential drop at the onset of the second plateau and the emergence of the third plateau, respectively, deviating from the typical discharge profiles. Furthermore, quantitative guidance for electrolyte screening and battery assembling is presented to selectively control LPS precipitation. The description of equilibrium potential could be used as a foundation for mechanism study and battery monitoring system development.

Changes in the Pattern of Weekdays Electricity Real Consumption during the COVID-19 Crisis

In this paper, using data from Romania, we analysed the changes in electricity consumption generated during the COVID-19 crisis, and the measures taken against the spread of the coronavirus to limit the effects of the pandemic. Using a seasonal autoregressive econometric model, we found that, beyond seasonal (weekly, monthly, quarterly, yearly) effects, the average daily electricity real consumption in Romania, during the state of the emergency period (16 March 16 to 14 May 2020) decreased by −194.8 MW (about −2.9%), compared to the historical data (2006–March 2022), and this decrease is not due to the action of some random factors, and it is not a manifestation of domain-specific seasonality. The literature discusses the hypothesis that during the pandemic time, the profile of daily electricity consumption on weekdays was close to the typical Sunday profile. We tested a similar hypothesis for Romania. As a methodology, we tried to go beyond the simple interpretation of statistics and graphics (as found in most papers) and we calculated some measures of distances (the Mahalanobis distance, Manhattan distance) and similarity (coefficient of correlation, cosines coefficient) between the vectors of daily electricity real consumptions, by hourly intervals. As the time interval, we have analysed, for Romania, the electricity real consumption over the period January 2006–March 2022, by day of the week and within the day, by hourly intervals (5911 observations). We found (not very strong) evidence supporting a hypothesis that, in the pandemic crisis, the profile of electricity consumption approaches the weekend pattern only for the state of the emergency period, and we could not find the same evidence for the state of the alert period (June 2020–March 2022). The strongest closeness is to the hourly consumption pattern of Saturday. That is, for Romania, in terms of electricity consumption, “under lockdown, every day is a Sunday” (Staffell) it is rather “under lockdown, every day is (almost) a Saturday”! During the state of the alert period, consumption returned to the pre-crisis profile. Since certain behaviours generated by the pandemic have been maintained in the medium and long term (distance learning, working from home, online sales, etc.), such studies can have policy implications, especially for setting energy policy measures (e.g., in balancing load peaks).

The Mineral Characteristic of Tropical Residual Soil using X-Ray Diffraction (XRD) and Scan Electron Microscopy (SEM)

Volcanic residual soil has unique characteristics due to weather and morphological influences. High temperatures and large amounts of rainfall made the rock weathering intense. Landslide events in volcanic residual soil of West Java are quite serious, more than 100 incidents in total a year. Landslides that occur due to unsaturated conditions on the top of the slope become saturated, so it is very important to conduct research on these tropical residual soil weathering zones to define its mineral characterization using Scan Electron Microscopy (SEM) and X-Ray Diffraction (XRD). From the research it was found that the dominant mineral types and contents were Halloysite and Kaolinite minerals. A typical mineral profile is found that is Goethite and Hematite minerals at the soil surface, Carbonate and Chlorite minerals in deeper soils and large amounts of Feldspar minerals in more deep layers. Because there are unique minerals at each depth of soil weathering, zone classification can be done easily starting from the Initial Leaching Zone at the deepest part where there is Feldspar, the Mineral Washing Zone there is Carbonate and Chlorite and the Oxidation Zone on the surface (there are Oxide and Hydroxide minerals). So that it can form a Residual Tropical Volcanic Weathering Profile.

Silicate and carbonate mixed shelf formation and its controlling factors, a case study from the Cambrian Canglangpu formation in Sichuan basin, China

Abstract Mixed sedimentation is mainly a phenomenon by which siliciclastic and carbonate are mixed under a similar sedimentary environment. The study of the composition of mixed rock can reflect the sedimentary environment. The mixed sediments of the Canglangpu formation in the eastern Sichuan basin are widely developed and exhibit well exploration prospects. In this study, a classification diagram of mixed sediments suitable for the Canglangpu formation was proposed by combining lithologic characteristics with logging data. Based on the observations of typical outcrop profiles, the identification of thin sections, and drilling and geological logging data, a model was established to identify the electrical responses of the mixed sedimentary rocks in the study area. The results show that (1) the Canglangpu formation can be vertically divided into two complete transgression-regression cycles with the lower part mainly consisting of sedimentary carbonate diamictite and the upper part principally composed of clastic diamictite; (2) mixed sediments in the Canglangpu formation can be divided into six classes, namely carbonate sandstone, argillaceous sandstone, sandy carbonate rock, argillaceous carbonate rock, sandy mudstone, and Carbonate mudstone; (3) the sedimentary environment of the Canglangpu formation be divided into (a) mixed sediments in the shore, which include mixed lagoon and mixed tidal flat, (b) mixed sediments in the shallow marine shelf, which includes mixed beach bar, terrigenous detrital mixed shelf, and carbonate mixed shelf; (4) a mixed shore-mixed shelf sedimentary model has been established; it says that the mixed sediments show obvious characteristics of ring-like development around underwater paleo-heights. The formation mechanism of mixed sedimentation in the eastern Sichuan basin is mainly controlled by the change of sedimentary facies belt, and the development intensity is mainly influenced by early tectonic movement and sea-level change.

Closed-form solutions to investigate the nonlinear response of foundations supporting operating machines under blast loads

Machine foundations are subjected to significant dynamic impacts. These impacts could spread to the surrounding regions, affecting workers, sensitive equipment in the same institution, or nearby areas. This study analyzes the response of machine-supporting foundations to harmonic and explosive loads under operational conditions and provides closed-form solutions for predicting responses in terms of displacement, velocity, and acceleration time-histories to two common types of blast loads: a more accurate typical profile and simplified triangular profile. The soil-machine foundation system is regarded as a single-degree-of-freedom (SDOF) system that exhibits elastic–perfectly flexible resistance behavior. For the analysis of the SDOF system, two cases are considered: one assumes that the supporting soil keeps elastic during the explosion, and the peak displacement is less than the elastic one, while the other assumes that the blast occurs in an elastic state, and the peak displacement occurs in a plastic state. By using the closed-form analytical solutions, a detailed parametric analysis is carried out to evaluate the impacts of significant soil-foundation system characteristics such as mass, stiffness, and damping ratio on the response-time history of machine foundations. The findings are compared to those reported in the literature, and relevant conclusions are derived. Obtained results demonstrated that, despite its simplicity and usage of only positive phase to simulate blast loads, the simplified model’s response behavior differs significantly from the typical one. Furthermore, the derived solutions are utilized to design the foundations supporting vibrating machines for both harmonic and blast loads in a variety of conceivable scenarios depending on the blast magnitude.

Development of a Swellable and Floating Gastroretentive Drug Delivery System (sfGRDDS) of Ciprofloxacin Hydrochloride.

Sangelose® (SGL) is a novel hydroxypropyl methylcellulose (HPMC) derivative that has been hydrophobically modified. Due to its high viscosity, SGL has the potential as a gel-forming and release-rate-controlled material for application in swellable and floating gastroretentive drug delivery systems (sfGRDDS). The aim of this study was to develop ciprofloxacin (CIP)-loaded sfGRDDS tablets comprised of SGL and HPMC in order to extend CIP exposure in the body and achieve optimal antibiotic treatment regimes. Results illustrated that SGL-HPMC-based sfGRDDS could swell to a diameter above 11 mm and showed a short floating lag time (<4 s) and long total floating time (>24 h) to prevent gastric emptying. In dissolution studies, CIP-loaded SGL-HPMC sfGRDDS demonstrated a specific biphasic release effect. Among the formulations, the SGL/type-K HPMC 15,000 cps (HPMC 15K) (50:50) group exhibited typical biphasic release profiles, with F4-CIP and F10-CIP individually releasing 72.36% and 64.14% CIP within 2 h dissolution, and sustaining release to 12 h. In pharmacokinetic studies, the SGL-HPMC-based sfGRDDS demonstrated higher Cmax (1.56-1.73 fold) and shorter Tmax (0.67 fold) than HPMC-based sfGRDDS. Furthermore, SGL 90L in GRDDS indicated an excellent biphasic release effect and a maximum elevation of relative bioavailability (3.87 fold). This study successfully combined SGL and HPMC to manufacture sfGRDDS that retain CIP in the stomach for an optimal duration while improving its pharmacokinetic characteristics. It was concluded that the SGL-HPMC-based sfGRDDS is a promising biphasic antibiotic delivery system that can both rapidly achieve the therapeutic antibiotic concentration and maintain the plasma antibiotic concentration for an extended period to maximize antibiotic exposure in the body.

Typical daily occupancy profiles of express hotels and its stochasticity effect on building heating and cooling loads

Occupancy schedule is a key input parameter affecting building performance simulation. Current research mainly applies the fixed occupancy schedules proposed in building codes, which is unsuitable for representing actual occupancy status. Unreasonable occupancy schedules will affect the prediction results of building energy consumption. This study collects the real-time occupancy data of six express hotels with 744 guest rooms, and determines typical occupancy profiles in three scenarios (single day of the year, spring/summer/autumn/winter, weekdays/weekends & holidays) by using the clustering method. The typical occupancy profiles for single day of the year are divided into seven categories based on different samples (all samples from the six hotels, and samples from each hotel). A Monte Carlo-based model is developed to convert the probability distribution functions of typical occupancy profiles to a time series of random occupancy (ROTS). Next, building heating and cooling load differences caused by the fixed occupancy schedules and the ROTS, three ROTS in different scenarios, and seven categories of the ROTS based on different samples are compared and analyzed by simulation. Clustering results indicate that the typical occupancy profiles can be divided into four main categories: ‘occupied for two nights’, ‘occupied from 0:00 to 14:00’, ‘occupied from 14:00 to 23:00’ and ‘vacant room’, respectively. Simulation results indicate that annual building loads resulting from ROTS is 72 kW h/(m2·a), 30%–50% lower than that resulting from the fixed occupancy schedules. The differences in the heating and cooling loads resulting from three ROTS in different scenarios and seven categories of the ROTS based on different samples are relatively small. Absolute error and root mean square percentage error are within 10% and 8%, respectively. Therefore, it is recommended that the ROTS for single day of the year processed from a large number of actual occupancy status can be used as an occupancy schedule to predict and assess the building heating and cooling loads. These conclusions can contribute greatly to accurate building load simulation and the optimization of building design strategies for express hotels.

A strategy resisting wrinkling of sandwich structures reinforced using functionally-graded carbon nanotubes

Sandwich structures have been widely applied in the wing and the horizontal tail of the aircraft, so face sheets of such structure might occur wrinkling deformation in the process of service, which will largely decrease capability of sustaining loads. As a result, this paper aims at proposing a reasonable strategy resisting wrinkling deformation of sandwich structures. To this end, an enhanced higher-order model has been proposed for wrinkling analysis of sandwich structures. Buckling behaviors of a five-layer sandwich plate are firstly analyzed, which is utilized to assess performance of the proposed model. Subsequently, wrinkling behaviors of four sandwich plates are further investigated by utilizing present model, which have been evaluated by using quasi three-dimensional (3D) elasticity solutions, 3D Finite Element Method (3D-FEM) results and experimental datum. Finally, the present model is utilized to study the buckling and the wrinkling behaviors of sandwich plates reinforced by Carbon Nano Tubes (CNTs). In addition, influence of distribution profile of CNTs on wrinkling behaviors has been analyzed, and a typical distribution profile of CNTs has been chosen to resist wrinkling deformation. Without increase of additional weight, the present strategy can effectively resist wrinkling deformation of sandwich plates, which is rarely reported in published literature.

Increased acylcarnitine ratio indices in newborn screening for carnitine-acylcarnitine translocase deficiency shows increased sensitivity and reduced false-positivity.

Carnitine-acylcarnitine translocase (CACT) deficiency is a rare autosomal recessive metabolic disorder of mitochondrial long-chain fatty acid oxidation. Newborn screening via tandem mass spectrometry (MS/MS) technology enables early diagnosis. However, previous analyses of MS/MS data of patients showed that some results were misdiagnosed because they did not show typical acylcarnitine profiles of CACT deficiency. This study aimed to identify additional indices to assist the diagnosis of CACT deficiency. To evaluate the acylcarnitine profile and the acylcarnitine ratios of individuals with CACT deficiency, the MS/MS data of 15 patients diagnosed via genetic testing were retrospectively analysed. The sensitivity and false-positive rates of primary acylcarnitine markers and ratio indices were validated using the data from 28,261 newborns and 53 false-positive cases. Additionally, the MS/MS data of 20 newborns carrying the c.199-10T>G mutation in SLC25A20 and 40 normal controls were compared to verify whether the carriers had abnormal acylcarnitine concentrations. The acylcarnitine profiles from 15 patients were classified into three categories using C12, C14, C16, C18, C16:1, C18:1, and C18:2 as the primary diagnostic markers. The first category represented a typical profile (P1-P6). The second category for patients P7 and P8 showed a significant decrease in the C0 level and a normal concentration of long-chain acylcarnitines. The third category for patients P9-P15 showed the presence of interfering acylcarnitines. The second and third categories may have been misdiagnosed. An acylcarnitine ratio analysis showed that C14/C3, C16/C2, C16/C3, C18/C3, C16:1/C3, and C16:1-OH/C3 were significantly increased in all 15 patients. The verification of 28,261 newborn screening results showed that the false-positive rate of ratios, except for (C16 + C18)/C0, was lower than that of acylcarnitine indices (0.02-0.08% vs. 0.16-0.88%). None of the single long-chain acylcarnitines could separate patients from the false-positive cases; however, all ratios produced good discrimination between the two groups. Based on the primary acylcarnitine markers alone, CACT deficiency can be misdiagnosed in newborn screening. The ratios of the primary markers (C16 + C18:1)/C2, C16/C2, C16:1/C3, and C16:1-OH/C3 can facilitate the diagnosis of CACT deficiency, thereby increasing sensitivity and reducing false-positivity.

A First Look at Spatially Resolved Balmer Decrements at 1.0 < z < 2.4 from JWST NIRISS Slitless Spectroscopy

We present the first results on the spatial distribution of dust attenuation at 1.0 < z < 2.4 traced by the Balmer decrement, Hα/Hβ, in emission-line galaxies using deep JWST NIRISS slitless spectroscopy from the CAnadian NIRISS Unbiased Cluster Survey (CANUCS). Hα and Hβ emission-line maps of emission-line galaxies are extracted and stacked in bins of stellar mass for two grism redshift bins, 1.0 < z grism < 1.7 and 1.7 < z grism < 2.4. Surface brightness profiles for the Balmer decrement are measured and radial profiles of the dust attenuation toward Hα, A Hα , are derived. In both redshift bins, the integrated Balmer decrement increases with stellar mass. Lower-mass (7.6 ≤ Log(M */M ⊙) < 10.0) galaxies have centrally concentrated, negative dust attenuation profiles whereas higher-mass galaxies (10.0 ≤ Log(M */M ⊙) < 11.1) have flat dust attenuation profiles. The total dust obscuration is mild, with on average 0.07 ± 0.07 and 0.14 ± 0.07 mag in the low- and high-redshift bins respectively. We model the typical light profiles of star-forming galaxies at these redshifts and stellar masses with GALFIT and apply both uniform and radially varying dust attenuation corrections based on our integrated Balmer decrements and radial dust attenuation profiles. If the Hα star formation rates (SFRs) of these galaxies were measured after slit-loss corrections assuming uniform dust attenuation with typical JWST NIRSpec slit spectroscopy (0.″2 × 0.″5 shutters), the total SFR will be overestimated by 6% ± 21% and 26% ± 9% at 1.0 ≤ z < 1.7 and 1.7 ≤ z < 2.4 respectively.

Nurse-led culturally relevant smoking reduction intervention among cardiovascular and respiratory patients in Pakistan.

Socioeconomically deprived populations are at greater risk for smoking-induced diseases and death, such as cancers, and cardiovascular and respiratory illnesses. The initiation of a nurse-led smoking cessation program in clinical practice is an effective method to enhance smoking cessation among cardiovascular and respiratory patients in Pakistan. This study aimed to evaluate the effectiveness of nurse-led smoking reduction intervention performed at out-patient clinics in Karachi, Pakistan. A single group pre-and post-test study was conducted on eligible patients (n=83) with a typical profile of cardiovascular and respiratory diseases in a tertiary care hospital from December 2020 to July 2021. The multi-modal nurse-led intervention consisted of two face-to-face motivational counseling (30-min) and free nicotine replacement therapy with telephonic counseling and follow-ups offered to all eligible patients for 2 months. The nurse-led intervention resulted in a significant decrease in daily cigarette consumption in most of the patients (75.9%) by 50% and 16.9% of the patients reported smoking abstinence (quitter) at 1-week follow-up (p<.001), verified by a CO breath test. A nurse-managed smoking reduction intervention for even a short duration (2 months) in clinics is an effective approach in enhancing smoking abstinence and reduction among cardiovascular and respiratory patients.

Response of the Stream Geomorphic Index to Fault Activity in the Lianfeng–Ningnan Segment (LNS) of the Lianfeng Fault on the Eastern Margin of the Tibetan Plateau

The response of the stream geomorphic index to fault activity is important for assessing the regional seismic hazard. The data used in this paper are 12 m resolution TanDEM-X data. The Fill tool in the Hydrology toolset in ArcGIS 10.5 was used to first process the digital elevation model (DEM), then analyse the flow direction of the DEM after filling and finally extract streams with catchment areas of more than 9 km2. Based on the DEM spatial analysis, the stream geomorphic index of the Lianfeng–Ningnan segment (LNS) of the Lianfeng fault was extracted, including the stream length gradient (SL) and the hypsometric integral (HI). This information, combined with the analysis of typical field geomorphology and terrace profiles, was used to define the fault activity period. To analyse the activity characteristics of the LNS, the LNS was divided into northern (Lianfeng to Jinyang), middle (Jinyang to Duiping town) and southern segments (Duiping town to Ningnan). The stream geomorphic index showed spatial variations, with mean SL and HI values of 384 and 0.45, respectively, in the northern segment; 175 and 0.41, respectively, in the middle segment; and 378 and 0.45, respectively, in the southern segment. These results indicate that the northern and southern segments of the LNS are more active than the middle segment, that there is little difference between the northern and southern segments, and that the activity of the middle segment is relatively weak. By comprehensively analysing the lithology, climate and tectonics in the LNS region, we conclude that tectonics are the main factor controlling the stream geomorphology in the LNS region. Based on this information and the analysis and dating of field geomorphology and terrace profiles, we found that the Lianfeng fault was active in the Holocene, which is consistent with the latest research results.

Factors affecting the stability of soil aggregates of plinthosols in the middle reaches of the Yangtze River

Soil aggregate stability is a key factor that affects soil erosion and ecological restoration. In this study, three typical plinthosol profiles in Wuhan (W), Yueyang (Y), and Jiujiang (J) were selected, and the mean weight diameter (MWD), geometric mean diameter (GMD), and fractal dimension were used as indicators of soil aggregate stability, as well as the erodibility factor (K value). Based on the end-member analysis, it appears that the plinthosols in the three profiles were wind-formed deposits, which greatly affected particle size and erodibility. There was a greater resistance to erosion among the plinthosols developed from finer grains than among those developed from coarse grains. The stability of aggregates in profiles W and Y decreased gradually with depth, while it varied little in profile J. The initial moisture content had a significant effect on the anti-erodibility of the plinthosols, and there were some differences between the profiles: in profile W, the anti-erodibility increased with the increase in initial moisture and reached its maximum value at the initial moisture content of 20%; in profiles Y and J, when the initial moisture content was 15%, the anti-erodibility was the highest. Reddishmatrixhadahigher anti-erodibility than white veins.ProfileJhadthelargeststability gap between white veins and reddishmatrix,followed by profileY and W. These results provide a theoretical basis for the conservation of soil and water in the Yangtze River middle reaches by revealing the stability characteristics of plinthosols.

CEREAL CROP IDENTIFICATION USING SENTINEL2 TIME SERIES, CASE OF SIDI BEL ABBES AREA

Abstract. The department of Sidi Bel Abbes is considered among the primary region producing cereal at the national level in Algeria. The study that we conducted is based on time series analysis using Sentinel2 images to monitor the cultivated cereal crops, combined with the field data including cereal plots for the growing season of 2020–2021.The methodology adopted in this study focused mainly on the processing of a Normalized Difference Vegetation Index (NDVI) time series. The analysis of the NDVI time series from October to July 2021, allowed us to determine the typical profiles of cereal crops, based on thresholding obtained to extract the areas cultivated by cereal crops. The geographical distribution of cereal in terms of area represents a high density of green biomass in the highlands and a low density of vegetation towards the plain and the highlands of the northwest area. The analysis of the profile’s growth for the cereal crops, allowed us to understand the behavior of the cereal crop during its development and to catch the relationship of these behaviors, the meteorological conditions and the agricultural practices followed.

Structural deformation of the Northern Monocline belt in the Kuqa depression and implications for the Cenozoic uplift history of the South Tianshan Mountains

The Northern Monocline zone is adjacent to the South Tianshan Mountains. Under continuous compression induced by the uplift of the South Tianshan Mountains in the late Cenozoic, structural deformation in the Northern Monocline zone is quite different from the layered contractional deformation in the whole Kuqa depression. Based on the latest three-dimensional seismic data, the structural deformation in the Northern Monocline zone is analyzed, and the typical seismic profile is restored to analyze the tectonic evolution. The results show that the salt structure is weakly developed in the Northern Monocline belt. The deformations in the supra-salt, salt and subsalt layers are relatively consistent, and only slight layered contraction is present locally in the western part. Structural deformation in the Northern Monocline belt is mainly controlled by the thickness of the original salt deposit, the uplift and tilting degree of the basement and subsalt layers, and the strong compressional stress from the South Tianshan Mountains. The restoration of the growth strata and tectonic evolution of the Northern Monocline area shows that the uplift of the South Tianshan Mountains began during the deposition of the Jidike Formation, has gradually increased since the Neogene and is at its peak at present.

Atypical presentation of tuberculosis: a case report highlighting the challenges of diagnosis and management

Tuberculosis (TB) remains a significant public health issue worldwide and can present with atypical symptoms, making it difficult to diagnose. Atypical TB symptoms include non-specific symptoms and extrapulmonary TB, and patients with comorbidities may present with atypical TB due to impaired immune function. TB treatment includes antibiotics, which can cause hepatotoxicity, and require close monitoring for signs of liver injury. A 32-year-old female with intellectual developmental disorders was admitted to the hospital with suspected pneumonia and acute respiratory viral infection. Despite initial treatment with antibiotics, her oxygen saturation decreased, and she developed recurrent pneumothorax on the right side and neutrophilic pleuritis. Computed tomography (CT) scans showed increasing infiltrative changes, and bronchoalveolar lavage eventually revealed Mycobacterium tuberculosis DNA, leading to the diagnosis of tuberculosis pneumonia with pleurisy. This case report highlights the challenges of diagnosing TB and the importance of maintaining a high index of suspicion for TB in patients who do not fit the typical profile of the disease. The case also emphasizes the potential for drug-induced liver damage with TB treatment and the need for close monitoring. Early diagnosis and appropriate management are crucial to prevent further complications and improve outcomes in patients with TB.

A PT-DA-Based electric taxi charging load prediction method considering environmental factors

The electric taxis (ETs) charging load is of great importance for the normal and the stable operation of power systems. A prediction model for the ET spatio-temporal charging load is proposed, which considers the drivers’ subjective decision-making and the ET travel patterns. First, an improved Gaussian mixture model with a genetic algorithm is developed based on the real ET data. Besides, a prospect theory based on the Dijkstra algorithm for choosing charging stations is put forward. Then, considering the ambient temperature, a calculation method for the remaining energy in the ET battery is utilized. Based on the refined travel patterns and the Monte Carlo method, the charging load in three scenarios are analyzed, which studies the influence of temperature. ET charging loads of different scales are obtained and the influence of charging load on the typical daily load profile is discussed. The simulation results show that the prediction models can combine the drivers’ psychology with the objective traveling time, and the average error between the real load and the predicted load is less than 1%.

Reading or Pretending to Read? Analysis of the Behavior of Primary School Students during a Reading Comprehension Test

The article describes the analysis of students’ behavior when performing a computerized test of reading comprehension. On a sample of 2157 fourth graders in Krasnoyarsk, using the method of latent profile analysis, five typical profiles of students were identified based on combinations of variables: “average text reading time”, “number of quick answers”, “amount of time to read auxiliary text”, “total test time”. The identified groups of students are interpreted using the assessment results. The identified profiles will be useful for a deeper interpretation of the assessment results and as a practical basis for developing methods for a differential approach to teaching.

Simulation of the December 2021 Marshall fire with a hybrid stochastic Lagrangian-cellular automata model

A stochastic model based on a combination of the cellular automata approach for forest fires and a random walk for firebrands and hot gases has been further developed and used to simulate the Marshall fire, Colorado, December 2021. Typical heat release profiles for burning wooden houses from the literature were used to distill information on the burning duration and ignition delay time needed to model the hours-long firebrand emission from wooden buildings in the Marshall area during this fire. In addition to information on vegetation and housing structures from in-person inspection, satellite images were used to estimate various model parameters. The results give reasonable predictions for the extent of the fire and its time evolution. A parametric analysis further highlighted the sensitivity of predictions to the parameters used in the model and suggested areas for improvement. The very low computational cost of the model, ease of operation, and acceptable accuracy suggest that the proposed framework can be used for operational decision-making and damage assessment.

Evaluation of Hydrogen Blend Stability in Low-Pressure Gas Distribution

Natural gas distribution companies are developing ambitious plans to decarbonize the services that they provide in an affordable manner and are accelerating plans for the strategic integration of renewable natural gas and the blending of green hydrogen produced by electrolysis, powered with renewable electricity being developed from large new commitments by states such as New York and Massachusetts. The demonstration and deployment of hydrogen blending have been proposed broadly at 20% of hydrogen by volume. The safe distribution of hydrogen blends in existing networks requires hydrogen blends to exhibit similar behavior as current supplies, which are also mixtures of several hydrocarbons and inert gases. There has been limited research on the properties of blended hydrogen in low-pressure natural gas distribution systems. Current natural gas mixtures are known to be sufficiently stable in terms of a lack of chemical reaction between constituents and to remain homogeneous through compression and distribution. Homogeneous mixtures are required, both to ensure safe operation of customer-owned equipment and for safety operations, such as leak detection. To evaluate the stability of mixtures of hydrogen and natural gas, National Grid experimentally tested a simulated distribution natural gas pipeline with blends containing hydrogen at up to 50% by volume. The pipeline was outfitted with ports to extract samples from the top and bottom of the pipe at intervals of 20 feet. Samples were analyzed for composition, and the effectiveness of odorant was also evaluated. The new results conclusively demonstrate that hydrogen gas mixtures do not significantly separate or react under typical distribution pipeline conditions and gas velocity profiles. In addition, the odorant retained its integrity in the blended gas during the experiments and demonstrated that it remains an effective method of leak detection.