Step Method Research Articles

Self-study and online interactive case-based discussion to improve knowledge of medical students in the COVID-19 era

BackgroundWe aimed to determine whether a new online interactive learning method for fifth-year medical students could improve their knowledge of pre- and postoperative care during the COVID-19 era.MethodsA retrospective cohort study was conducted from June 2020 to May 2022 during the pre- and postoperative care course for fifth-year medical students in a university hospital in southern Thailand. Students in the 2020 cohort received only a 60-minute lecture on spinal anesthesia via Zoom while a 3-step online interactive learning method was used for the 2021 cohort. Step 1: students performed self-study comprised of video lectures and case-based discussion one week before the online class with a pre-test submitted via Google forms. Step 2: an online interactive case-based discussion class was performed via Zoom by two experienced anesthesia staff and a post-test was submitted by the students via Google forms. Step 3: a small group discussion of course evaluation between 13 representatives of students and anesthesia staff was performed via Zoom. A comparison of the post-test and pre-test scores containing 20 multiple choice questions as well as the final exam scores before (2020) and after (2021) the new interactive learning was performed using a t-test.ResultsThere were 136 and 117 students in the 2020 and 2021 academic years, respectively. The final mean (SD) exam scores for the 2020 and 2021 academic years were 70.3 (8.4) and 72.5 (9.0), respectively with a mean (95% confidence interval (CI)) difference of 2.2 (4.3, -0.02). In 2021, the mean (95% CI) difference between the post-test and pre-test scores was 5.8 (5.1, 6.5). The student representatives were satisfied with the new learning method and gave insightful comments, which were subsequently implemented in the 2022 academic year course.ConclusionThe new interactive learning method improved the knowledge of fifth-year medical students attending pre- and postoperative care course during the COVID-19 era. The final exam scores may not be suitable to represent the overall outcomes of the new interactive learning method. Using an online two-way communication method can improve the overall satisfaction and course adaptation during the COVID-19 era.

Study on the Two-Step Construction Method of Super Large Cross-Section Tunnels Crossing Karst Cave Areas

To explore the solution of the two-step method applied in the rapid construction of super large cross-section tunnels passing through IV-and V-grade surrounding rock sections in karst cave areas, based on an engineering example of the Lianhuashan Tunnel, we use the numerical calculation method to analyze the stability of surrounding rock and the design parameters of the control measures for super large cross-section tunnels during the construction of the step method. The calculated results show that the working face of IV-grade surrounding rock can be stabilized by an advanced small pipe, and the stability of the supporting structure should be controlled mainly by IV-grade surrounding rock. In order to control the stability of the tunnel face, it is necessary to use an advanced large pipe shed in the surrounding V-grade rock. The reinforcement range of the advanced large pipe shed is 120° and the length is 20 m. This is the most economical design parameter of the advanced large pipe shed, ensuring the deformation control effect. For control of the stability of the supporting structure, under the condition that the working space is suitable for large machinery, the settlement of the arch of the supporting structure can be obviously reduced by shortening the step cycle footage and reducing the step length, and the peripheral convergence of the supporting structure can be obviously reduced by reducing the step height. After comprehensive analysis and considering the development of karst caves, the advanced support measures, design parameters, bench excavation design parameters, initial support measures, karst cave treatment measures, and bench construction process of IV- and V-grade surrounding rock is determined. The application verification shows that the research results have a good control effect on the stability of the surrounding rock and cave and are suitable for large-scale mechanical operations, which can significantly improve the excavation speed of the super large cross-section tunnel passing through the IV- and V-grade surrounding rock sections in the karst cave area.

Preparation of microfibrillated cellulose by in situ and one step method using calcium hydroxide as swelling and grinding agent

Abstract Calcium hydroxide was used as a swelling agent and grinding aid to grind together with cellulose raw materials to prepare microfibrillated cellulose (MFC). Carbon dioxide was introduced to obtain MFC coated with calcium carbonate (CMFC). The effect of calcium hydroxide dosage on the fibrillation process of cellulose materials and the characteristics of MFCs and CMFCs were studied. Results show that when the dosage of calcium hydroxide was 5 % (based on cellulose materials), calcium hydroxide could be completely dissolved in water and had a swelling effect on cellulose materials. When the dosage reached 10 %, undissolved calcium hydroxide particles could serve as grinding media to assist in the fibrillation of cellulose materials. When the dosage exceeded 50 %, the auxiliary grinding effect of calcium hydroxide was more obvious. After accelerated carbonation, the generated calcium carbonate nanoparticles were coated on the surface of MFC, which increased its viscosity and decreased water retention value. The presence of calcium carbonate also facilitated the concentration, redispersion, and drying of MFC. The pretreatment, mechanical fibrillation, and accelerated carbonation were carried out in the same equipment without the need for heating or washing. Therefore, this study provides a in situ and one step method for the preparation of MFC.

Green Synthesis of Silver Nanoparticles Using Microbial Biosurfactant Produced by a Newly Isolated Klebsiella sp. Strain RGUDBI03 Through a Single Step Method and Exploring its Role in Enhancing the Chickpea and Rice Seed Germination

Green Synthesis of Silver Nanoparticles Using Microbial Biosurfactant Produced by a Newly Isolated Klebsiella sp. Strain RGUDBI03 Through a Single Step Method and Exploring its Role in Enhancing the Chickpea and Rice Seed Germination

Rare and unexplored traditional waste food processing and fermentation methods of the meitei-pangal community of Manipur: A northeastern state of India

This research examines rare and unexplored traditional waste food processing and fermentation methods. Processed waste foods as well as fermented foods represent an important segment of the most commonly consumed foodstuffs and the nutrient suppliers of the living populations across the world. Soibum, hawaijar, ngari, hentak, and yongchak are some of the most commonly consumed processed waste foods and fermented foods among the natives of Manipur. To our knowledge, no proper compilation of traditional methods of waste food processing and the fermentation processes of the meitei-pangal community of Manipur has been carried out yet. In this study, the traditional methods of processing waste foods and fermentation steps of foodstuffs commonly consumed by the Meitei pangal community of Manipur are surveyed and recorded for the first time. The results of the study reveal that six unique and diverse categories and ways of processing waste foods and the fermentation of food products locally known as Yongchak, chakring, ngari, hentak, soibum, and hawaijar were practiced by every family of the meitei-pangal community of Manipur using local stinky beans (Parkia sp.), cooked rice-based products, local fish (Puntius sp.), bamboo shoots (Bambusa sp.), and soybean products. The study will offer a new understanding of the waste food processing and fermentation processes of some of the most commonly consumed foodstuffs by the natives of the northeastern states of India, with numerous health advantages for prospective future drug discoveries and nutraceutical applications.

Structural and optical properties of sulfurized Cu2ZnSnS4 films grown by one step method using calcined powders for electrical properties study of Al/p-Cu2ZnSnS4 Schottky diode

Structural and optical properties of sulfurized Cu2ZnSnS4 films grown by one step method using calcined powders for electrical properties study of Al/p-Cu2ZnSnS4 Schottky diode

Influence of length of resonance tubes on multi-stage looped thermoacoustic electric generator

Resonance tubes are often used to connect multi-stage looped thermoacoustic heat engine and linear alternators to form a multi-stage looped thermoacoustic electric generator. In this paper, we experimentally investigate the performance of a multi-stage looped thermoacoustic electric generator with two sets of resonance tubes of different lengths. With the increase of the length of resonance tubes from 1.5 m to 2 m, the system frequency decreases from 70 Hz to 62 Hz. The maximum output acoustic power increases from 6.97 kW to 8.16 kW, and the maximum output electric power increases from 5.09 kW to 6.24 kW. Meanwhile, the maximum thermoacoustic efficiency increases from 23.08 % to 23.94 %, the maximum acoustic-to-electric efficiency increases from 78.03 % to 82.06 % and the maximum thermal-to-electric efficiency increases from 17.79 % to 19.64 %. Numerical simulation is also conducted based on a 3-step coupling method and validates the experimental results. This study demonstrates that adjusting the length of resonance tubes in a multi-stage looped thermoacoustic electric generator is an effective way to tune the frequency as well as to improve the coupling between the multi-stage looped thermoacoustic heat engine and linear alternators.

Research on formation mechanism and output effect of wind turbine ice-covered blades

Considering the physical characteristics of wind turbine wing icing, icing synthesis rate, and icing type, we selected the icing type and surface roughness of ice-coated blades as sensitive parameters. The focus of our research was on the equivalent particle roughness height correction model, and we numerically analyzed the two icing processes (frost ice and clear ice) on wind turbine blade surfaces by combining FENSAP-ICE and FLUENT analysis tools. We predicted the ice type on blade surfaces using a multi-time step method and analyzed how variations in icing shape and ice surface roughness affect the aerodynamic performance of blades during frost ice formation or clear ice formation. Our results indicate that differences in blade surface roughness and heat flux lead to disparities in both ice formation rate and shape between frost ice and clear ice. Clear ice has a greater impact on aerodynamics compared to frost ice, while frost ice is significantly influenced by the roughness of its icy surface. These findings can serve as valuable references for wind power operators and manufacturers seeking solutions to issues related to blade surface icing under extremely cold conditions.

Relationship Quality Among Persons with Serious Mental Illness and Their Relatives: Rates and Correlates.

Supportive family relationships for persons with serious mental illness (SMI) are correlated with positive functional, health and mental health outcomes and are essential to the recovery process. However, there has been a dearth of research on positive family dynamics. Using multivariate logistic regression with a U.S. community-recruited sample of persons with SMI (N = 523), we examined the extent to which demographics, clinical characteristics, and supportive and problematic relationship interactions were associated with relationship quality with reference relatives (RR). Secondarily, we tested whether the relationship between routine limit-setting practices by RR toward participants and relationship quality was significantly mediated by perceived emotional overinvolvement using Baron and Kenny's four step method. High levels of relationship quality were reported by two-thirds of the sample. Relationship quality was positively associated with frequency of contact between participants and RR, participants helping RR with activities of daily living, and caregiving provided by RR to participants. High relationship quality was negatively associated with RR being parents or other family members (compared to romantic partners), perceived emotional overinvolvement of RR, and psychological abuse by RR toward participants. Clinical and demographic characteristics were not associated with relationship quality. Perceived emotional overinvolvement was found to be a mediator between routine limit-setting practices and relationship quality. These results can help direct clinicians in targeting factors that will likely enhance the process of recovery.

Validation of a poll shot captive bolt as a single step method of euthanasia of cattle

Euthanasia should occur with minimal pain and distress for the animal and the person administering the procedure. The AVMA Guidelines for Euthanasia lists a frontal shot as the recommended anatomical location for both penetrating cap­tive bolt and gunshot euthanasia. However, in many situations access to the frontal site is not possible or may cause exces­sive distress to the animal. The objective of this study was to validate the effectiveness of a penetrating captive bolt when positioned behind the poll as a single step method for humane euthanasia of cattle.

Differing Content and Language Based on Poster-Patient Relationships on the Chinese Social Media Platform Weibo: Text Classification, Sentiment Analysis, and Topic Modeling of Posts on Breast Cancer.

Breast cancer affects the lives of not only those diagnosed but also the people around them. Many of those affected share their experiences on social media. However, these narratives may differ according to who the poster is and what their relationship with the patient is; a patient posting about their experiences may post different content from someone whose friends or family has breast cancer. Weibo is 1 of the most popular social media platforms in China, and breast cancer-related posts are frequently found there. With the goal of understanding the different experiences of those affected by breast cancer in China, we aimed to explore how content and language used in relevant posts differ according to who the poster is and what their relationship with the patient is and whether there are differences in emotional expression and topic content if the patient is the poster themselves or a friend, family member, relative, or acquaintance. We used Weibo as a resource to examine how posts differ according to the different poster-patient relationships. We collected a total of 10,322 relevant Weibo posts. Using a 2-step analysis method, we fine-tuned 2 Chinese Robustly Optimized Bidirectional Encoder Representations from Transformers (BERT) Pretraining Approach models on this data set with annotated poster-patient relationships. These models were lined in sequence, first a binary classifier (no_patient or patient) and then a multiclass classifier (post_user, family_members, friends_relatives, acquaintances, heard_relation), to classify poster-patient relationships. Next, we used the Linguistic Inquiry and Word Count lexicon to conduct sentiment analysis from 5 emotion categories (positive and negative emotions, anger, sadness, and anxiety), followed by topic modeling (BERTopic). Our binary model (F1-score=0.92) and multiclass model (F1-score=0.83) were largely able to classify poster-patient relationships accurately. Subsequent sentiment analysis showed significant differences in emotion categories across all poster-patient relationships. Notably, negative emotions and anger were higher for the "no_patient" class, but sadness and anxiety were higher for the "family_members" class. Focusing on the top 30 topics, we also noted that topics on fears and anger toward cancer were higher in the "no_patient" class, but topics on cancer treatment were higher in the "family_members" class. Chinese users post different types of content, depending on the poster- poster-patient relationships. If the patient is family, posts are sadder and more anxious but also contain more content on treatments. However, if no patient is detected, posts show higher levels of anger. We think that these may stem from rants from posters, which may help with emotion regulation and gathering social support.

A pressure-projection pre-conditioning multi-fractional-step method for Navier–Stokes Flow in Porous Media

A new pressure-projection pre-conditioning multi-fractional-step (PPP-MFS) method for incompressible Navier–Stokes flow in porous media is presented. This fractional step method is applied to decouple the pressure and the velocity; thereby, overcoming the computational costs and difficulty associated with the resolution of the nonlinear term in the Navier–Stokes equation for fine geometric models. Specifically, time evolution is decomposed into a sequence of multi-fractional solution steps. In the first step, an elliptic problem is solved for pressure (p) with a no-slip boundary condition. This gives the Stokes pressure and velocity fields. In the second step, the obtained pressure p is then projected onto the field p∗ and used to solve for velocity field (u) required for the pre-conditioning of the solution to the Navier–Stokes equation. The pressure and velocity fields are obtained from the solution of the Navier–Stokes equation in the third step. Numerical and geometric discretisation of porous samples were carried out using finite-element method. For flow in simple channel models represented by two- and three-dimensions and in systems with high conductivity, the Stokes and Navier–Stokes numerical solutions produced close pressure and velocity field approximations. For flow around a cylinder, computation time is consistently higher in the Navier–Stokes equation by a factor of 2 with a pronounced non-symmetric pressure field at high mesh refinements. This computation time is desirable given that Navier–Stokes computation without preconditioning can be orders of magnitude more expensive.

Pressure boundary conditions for immersed-boundary methods

Immersed boundary methods have seen an enormous increase in popularity over the past two decades, especially for problems involving complex moving/deforming boundaries. In most cases, the boundary conditions on the immersed body are enforced via forcing functions in the momentum equations, which in the case of fractional step methods may be problematic due to: i) creation of slip-errors resulting from the lack of explicitly enforcing boundary conditions on the (pseudo-)pressure on the immersed body; ii) coupling of the solution in the fluid and solid domains via the Poisson equation. Examples of fractional-step formulations that simultaneously enforce velocity and pressure boundary conditions have also been developed, but in most cases the standard Poisson equation is replaced by a more complex system which requires expensive iterative solvers. In this work we propose a new formulation to enforce appropriate boundary conditions on the pseudo-pressure as part of a fractional-step approach. The overall treatment is inspired by the ghost-fluid method typically utilized in two-phase flows. The main advantage of the algorithm is that a standard Poisson equation is solved, with all the modifications needed to enforce the boundary conditions being incorporated within the right-hand side. As a result, fast solvers based on trigonometric transformations can be utilized. We demonstrate the accuracy and robustness of the formulation for a series of problems with increasing complexity.

A multi-objective model for selecting response strategies of primary and secondary project risks under interval-valued fuzzy uncertainty

Risks are uncertain events that can affect criteria such as project cost, quality, and completion time and ultimately lead to project failure. That is why the project risk management process, which is one of the most fundamental parts of project management, must be done properly. In this paper, a new multi-objective fuzzy model is proposed to respond appropriately to the primary and secondary project risks. The contributions, such as risk interdependency, considering the project with multi-mode activities, resource considerations, as well as attention to interval-valued fuzzy uncertainties are regarded simultaneously for the first time. The purpose of the proposed multi-objective mathematical model is to minimize cost, quality reduction, and project completion time. Then, a new two-stage uncertain solution approach is introduced in this paper. In this solution approach, using an equivalent method in the first step and then using an extended multi-choice goal programming method in the second step, for both lower and upper limits of the membership functions for interval-valued fuzzy numbers, the computational processes are performed. To show the application and effectiveness of the proposed model, a case study adapted from the literature is given. Finally, sensitivity analysis is conducted to analyze the behavior of the developed mixed-integer programming model. The analysis of obtained results indicates that the utilization of the proposed model leads to better and more appropriate solutions.

Effect of natural thickener on printing performance over cotton woven fabric

Execution of natural thickener (wild taro corm) over pretreated cotton woven fabric with reactive dye has been explored in this research work. Taro root was collected from Sherpur in Bangladesh and made into a fine powder using a grinder. Thickener pastes were prepared by using different concentrations of taro powder, then their viscosity was measured to find out the difference with sodium alginate thickener, which is traditionally used for reactive printing. A suitable thickener stock paste concentration was selected from a number of trials and depending on the result of visual sharpness of the printed samples. A suitable reactive printing method was selected between all in (1 step) and 2 step methods of reactive printing and finally the amount of thickener on the printing recipe was optimized. The color fastness to wash, color fastness to rubbing, bending length, K/S value, levelness, penetration%, print paste adds on and visual sharpness were measured to assess the printing quality. The findings indicate that when Taro corm powder is combined with boiled water, it produces a solution with higher viscosity. Additionally, a mixture of 15 % taro and boiled water yields the most distinct print outline. Comparatively, the 2-step reactive printing method offers a superior outline compared to the 1-step (all in one) method. Moreover, using 50 to 60 gm of taro corm thickening paste for every 100 g of print paste results in a higher K/S value. The results revealed that the wild taro corm could be used successfully as thickener for reactive printing. Finally, the cost was also calculated, and it was found economical as well compared to sodium alginate.

Numerical study of shock wave boundary layer interaction flows using a novel turbulence model

This study proposes a novel partial average fluctuation velocity (PAFV) turbulence based on the PAFV and the average strain rate tensor, which is used to calculate the shock wave boundary layer interaction flows, including cascade flow and transonic compressor flow. In order to illustrate the adequacy, the calculation results of several other turbulence models were also compared with PAFV, including k-ω, shear stress transport, SA-neg (negative Spalart-Allmaras), and stress-BSL (ω-based Reynolds stress model). The suitability of the PAFV turbulence model was initially tested by calculating the transonic flow in the L030-4 cascade. Subsequently, numerical computations were performed for the 3D (three-dimensional) National Aeronautics and Space Administration Rotor 67 transonic compressor rotor. In the numerical simulation, the flow control equations were transformed in a general curvilinear coordinate system for precision enhancement, and the spatial discretization of control equations was executed using the finite difference method. The convection term was processed using the Steger–Warming flux vector splitting method, the diffusion term was discretized using a second-order central difference scheme, and the time derivative term was discretized using the third-order Runge–Kutta method. A parallel computing strategy with multi-block partitioning was employed to speed up the calculations and facilitate faster convergence alongside a local time step method. All numerical computation procedures were written in Python, revealing the following: (1) The PAFV turbulence model aptly simulates the transonic flow within the cascade channel. The shock wave pattern in the cascade channel aligns well with the experimental schlieren images. (2) During the Rotor 67 transonic compressor rotor calculation, the flow–pressure ratio, flow efficiency, and inlet and outlet total temperatures and pressures align well with the experimental data. Furthermore, the resolution of the flow field structure related to the interaction between the tip leakage vortex and channel shock wave is high. (3) The turbulence model uses PAFV as the turbulence velocity scale, thereby suppressing the fluctuation velocity and turbulence viscosity near shock wave areas, preventing excessive turbulence viscosity. Moreover, PAFV inherently exhibits transport properties and anisotropic characteristics, making it well-suited for handling transonic compressor flows.

High energy supercapacitance of magnetic PANI/Ni2O3 nanocomposite and its magnetic structural repair

A magnetically auto healable and robust supercapacitor from a nanocomposite of PANI68.1 %: Ni2O331.9 % (PNi) synthesized in an in situ single step method, is achieved. PNi provided an exceptional character of healing the structural damage of PANI by the magneticity of Ni2O3 nanoparticles and showed a feature of increase in energy storage with increase in No. of charge/discharge cycles. The PNi exhibited a cyclic stability up to 16,800 cycles without significant reduction in initial Cs. The energy storage parameters achieved after 10,000 cycles are specific capacitance (Cs) of 347.6 F g−1, specific energy (E) of 69.52 W h kg−1, which is in the regime of E of Ni-metal hydride batteries of 0.9–1.3 V potential range, and specific power (P) of 8.571 kW kg−1 at 3 A g−1. Therefore, the PNi would be of a potential electrode material for the fabrication of long withstanding, robust and self - magnetically healable supercapacitor that delivers high energy.

Numerical modelling of continuous casting of round billets with turbulence in the melt

The present work aims to solve the continuous casting benchmark problem in axisymmetry with turbulence in the melt by the meshless method. The physical model of the liquid-solid system that involves mass, momentum and energy conservation is formulated in the mixture continuum approximation. The melt is assumed Newtonian and incompressible. A k-epsilon Reynolds averaged Navier-Stokes turbulence model is implemented with Abe-Kondoh-Nagano closures. The mushy region is modelled as a Darcy porous media with the Kozeny-Carman permeability model. The solution of partial differential equations is implemented locally using collocation with radial basis functions and explicit time-stepping. The velocity pressure coupling is performed using the fractional step method. The validation of the model is assessed by comparing its outcomes with the results of the finite volume method. A sensitivity study of the varying casting speed and temperature on the velocity, temperature, and solid fraction fields is shown.

An experimental investigation of tensile residual strength of repaired composite laminates after low velocity impact

Low Velocity Impact (LVI) of Carbon Fibre Reinforced Polymer (CFRP) components are common during the manufacture and in-service life of aerostructures. However, the resulting effect on structural mechanical properties has not been extensively studied when the damage occurs on repaired components, which are already compromised to some degree. This research considers the relative mechanical performance of CFRP parts that are (1) pristine, (2) repaired using the stepped scarf method, and (3) repaired then impact damaged (low velocity impact at 5 J energy). For each case, subsurface damage was visually investigated and detailed measurements taken including impact load–time/energy–time behaviour, and post-impact tensile maximum force, stress and strain (and homogenised Young's modulus) before fracture. Further, three different repair patch sizes were considered. The experiments show that negligible surface impact damage was present in all repair cases but that delamination and debonding occurred for all but large repairs. For small and medium repair patches, 71% and 83% of the static strength of pristine samples were observed, with nearly full recovery for large repairs. After LVI, the strength of small repairs did not decrease whereas that of medium repairs declined to 77%. Interestingly, LVI did not have any impact on load bearing capability of large repairs. Stiffness measurements increased with repair size, even exceeding the value for pristine samples in some cases. The maximum stresses sustained were 67%, 77% and 85% that of a pristine sample for small, medium, and large repairs respectively.

A 3-step method for preparing cryopreserved samples of apheresis products for post-thaw analysis yields a higher percentage of viable cells.

Standard flow cytometry protocols for CD34+ cell enumeration designed for fresh samples are not appropriate for cryopreserved products. Special protocols have been developed to remove the cryoprotectant by quickly washing a freshly thawed sample. Exposing cells to a large volume of hypotonic solution and subsequent washing process was hypothesized to cause lab-induced cell death. Moreover, standard gating strategies must be altered to avoid reporting falsely high viabilities. We developed a novel method whereby thawed samples were diluted step-wise to 1:2 by 3 additions of 1/3 sample volume using 1% Human Albumin in Dextran 40 (10% Low Molecular Weight Dextran in 0.9% NaCl) separated by 5 min between each addition. An additional 1:10 dilution was required to obtain a desired cell concentration for flow cytometry testing resulting in a 1:20 dilution. Twenty samples were tested simultaneously in a method comparison; the new method demonstrated significant increases in mean cell viabilities for white blood cells, hematopoietic progenitor cells, and T cells as well as reduced standard deviations for each parameter. Slow, step-wise dilutions of freshly thawed samples of cryopreserved apheresis products to 1:20 yielded higher and more precise viability measurements compared to quickly washing samples to remove DMSO.