Control Factors Research Articles

Electronic Cigarette and Heated Tobacco Product Use and Their Association With Tobacco Control Factors Among Adults in Indonesia, Kazakhstan, and the Philippines.

Data on e-cigarette (EC) and heated tobacco product (HTP) use and the reasons for their use are useful for policy making. We report comparable nationally representative estimates of EC and HTP use and their associated factors. Global Adult Tobacco Survey data from Indonesia (2021), Kazakhstan (2019), and the Philippines (2021) were analyzed. The weighted prevalence rates and 95% CI of EC and HTP awareness, current use, and ever use, and their distribution by cigarette smoking status were calculated. Binary logistic regression analyses assessed socioeconomic, and tobacco control factors associated with EC and HTP use. The prevalence (%) of EC awareness, ever use and current use were 48.7-69.4, 3.6-8.8, and 1.9-3.0, respectively. The prevalence(%) of HTP awareness, ever use and current use were 2.7-21.7, 0.2-2.1, and 0.1-1.2, respectively. The main reasons for EC and HTP use were attractive flavors(45.8%-73.9%), less harmful than smoking(23.0%-70.1%), and enjoyment(40.8%-76.7%). Avoiding going back to smoking(0.9%-54.4%) and quitting smoking(19.4%-49.8%) were less frequently cited reasons (except in the Philippines). EC/HTP use was associated with younger age, higher education and wealth, current/past smoking, exposure to information about the dangers of tobacco use, and advertisements about tobacco products and smoke-free rules at home. The prevalence of EC and HTP use was higher among younger men with higher education and wealth, and current/past smoking. EC and HTP use should be closely monitored. Regulations to restrict the widespread marketing and sales of EC and HTP are needed to prevent the escalation of their use. The population-level data provide the benchmark for future monitoring use of e-cigarettes and HTPs and identify population subgroups for future surveillance in low- and middle-income countries. The association of EC/HTP use with tobacco control-related factors provides leads for policies that should be formulated and implemented to regulate the product contents, marketing, and sales of EC and HTP.

Clinical study on the characteristics and related influencing factors of deliberate drug ingestion in adolescents.

To analyze the characteristics of deliberate drug ingestion in adolescents and its related influencing factors. This was a retrospective study. A total of 158 cases of deliberate drug ingestion as observation group and 160 cases of other diseases in adolescents as control group were treated in the Emergency Department of Baoding Hospital of Beijing Children's Hospital Affiliated to Capital Medical University from January 2020 to December 2022. The clinical characteristics of adolescents who engaged in deliberate drug ingestion were analyzed, and various factors that could potentially influence deliberate drug ingestion in adolescents were subjected to both univariate and multivariate analysis. There was a progressive increase in the number of patients presenting with mental health issues year by year. Univariate analysis showed that family type, guardian's education level, place of residence, whether they were only children, parents' knowledge of medication, awareness of medication safety, depression/anxiety, negative life events, and social support were risk factors for deliberate drug ingestion in adolescents (all p<0.05). Logistic regression analysis showed that family type, parents' knowledge of medication, awareness of medication safety, whether they were depressed/anxious, negative life events, and social support were independent risk factors for deliberate drug ingestion in adolescents (p<0.05). The incidence of deliberate drug ingestion in adolescents is increasing year by year, and their behavior is influenced by multiple factors. Interventions should be targeted at controllable influencing factors to prevent or reduce deliberate drug ingestion in adolescents.

Abnormal Changes Diagnosis and its Control Factors of Water and Sediment Discharge in the Lower Reaches of the Three Largest Rivers in China from 1960 to 2020

Abnormal Changes Diagnosis and its Control Factors of Water and Sediment Discharge in the Lower Reaches of the Three Largest Rivers in China from 1960 to 2020

Study on the Hydration Heat Effect and Pipe Cooling System of a Mass Concrete Pile Cap

Under the action of cement hydration heat, the construction environment, thermal insulation measures, and pipe cooling systems, a mass concrete pile cap is subject to a complex internal temperature field, which makes it difficult to control its internal surface temperature difference (TISTD), the internal adiabatic temperature rise (TIATR), and the surface temperature (TST). In this study, a mass concrete pile cap of a very large bridge (the length, width, and height were 26.40 m, 20.90 m, and 5.00 m, respectively, and the central-pier pile cap was constructed with C40 concrete) was taken as the research object. The control factors affecting the temperature field of the pile cap were determined by comparing the field temperature measurements with the values calculated with finite element software simulation analysis. By using Midas Civil (2022 v1.2) and Midas FEA (NX 2022) finite element software, these factors (the concrete mold temperature, the concrete surface convection coefficient, the ambient temperature, the pipe cooling system parameters, etc.) were numerically analyzed, and their influence laws and degrees were determined.

Overall aerodynamic performance of the airfoils with different amplitudes via a fuzzy decision making based Taguchi methodology

In this study, the overall aerodynamic performance of the airfoils with variable amplitude geometric structure for lift-type vertical axis wind turbine has been analyzed and optimized using Fuzzy Analytic Hierarchy Process (AHP)-Fuzzy COmbinative Distance-based Assessment (CODAS) based on Taguchi Method. In the design of the experiment, leading edge (LE) tubercle airfoil models, Reynolds number, and angle of attack are utilized as the control factors. Drag, lift, and lift to drag ratio performances by comparing the airfoils according to the baseline model are calculated and the combination of these performances is considered as the overall aerodynamic performance response. The experiments are carried out according to the orthogonal matrix L18. Since the importance of each response is different on lift-type vertical axis wind turbines, the importance weights of these responses were obtained by Fuzzy AHP according to the evaluation of the decision maker. Multiple responses are converted into a single response (the overall aerodynamic performance) via Fuzzy CODAS which enables to model uncertainty in order to overcome the physical effects that may arise in experiments. Thereby, a multi objective Taguchi methodology was applied for the overall aerodynamic performance with a novel Fuzzy logic based multi criteria decision analysis approach. As a result, Model-4, having tubercle design parameters of amplitude of 0.025c and 0.0125c and wavelength of 0.5c and 0.125c, was found to have the best performance with the novel Taguchi approach, which saves time and cost. In addition, it has been determined that the airfoils, Reynolds number and angle of attack are significant and what level of contribution to the overall aerodynamic performance. At this point, the most important control factor has emerged as the angle of attack.

Achieving partial nitrification by sludge treatment using sulfide: Optimal conditions determination, long-term stability evaluation and microbial mechanism exploration

This study proposes an innovative strategy for achieving PN in synthetic domestic wastewater by side-stream sludge treatment using sulfide as the sole control factor. By conducting controllable batch experiments and response surface analysis, optimal sulfide treatment conditions were firstly determined as 90 mg/L of sulfide, 7.5 of pH, 100 rpm of rotation and 12 h of treatment time. After treatment, half of ammonia oxidizing bacteria (AOB) activity remained, but nitrite oxidizing bacteria (NOB) activity was barely detected. Nitrite accumulation rate of long-term running PN steadily reached 83.9 % with 99.1 % of ammonia removal efficiency. Sulfide treatment increased community diversity and facilitated stability of microbiota functioning with PN phenotype, which might be sustained by the positive correlation between ammonia oxidation gene (amoA) and sulfur oxidation gene (soxB). Correspondingly, the network analysis identified the keystone microbial taxa of persistent PN microbiota as Nitrosomonas, Thauera, Truepera, Defluviimonas and Sulitalea in the later stage of long-term reactor.

Process Optimization for Biosurfactant Production by Bacillus aryabhattai SPS1001 using Taguchi Method.

This study employs Taguchi design of experiments (DOE) to optimize biosurfactant yield by analyzing the impact of various input parameters. Signal-to-noise ratio analysis was utilized for optimization, corroborated by ANOVA findings. Regression equations depicted response behaviour and are validated through a confirmation test. Taguchi methodology identified optimal conditions for maximum biosurfactant yield: agitation (180rpm), inoculum size (2%), beef extract (5g/L), diesel (20ml/L), peptone (5g/L), NaCl (7g/L), incubation time (4days), pH (7.9), and yeast extract (6g/L). This yielded an 8.33% increase to 1.53g/L, with initial optimum parameters projecting 1.41g/L. ANOVA ranked and quantified control factor contributions, revealing agitation's significant (31.41%) impact on yield. The study underscores the viability of Taguchi's optimal conditions for substantial yield improvement within specific ranges. The strong alignment between expected and experimental yields affirmed the reliability of developed models for optimal yield selection. This study underscores the power of statistical techniques like Taguchi DOE and ANOVA in systematically enhancing biosurfactant production by Bacillus aryabhattai SPS1001 and paves the way for future advancements in bioprocess optimization.

Glycemic Control and Cardiometabolic Risk in Black Zimbabweans with Type 2 Diabetes Mellitus.

Type 2 diabetes mellitus (T2DM) frequently presents with modified cardiometabolic risk profiles, indicative of an elevated susceptibility to cardiovascular disease (CVD). Cardiometabolic risk factors such as obesity, hyperglycemia, hypertension, insulin resistance and dyslipidemia are known contributors to increased CVD hazard in individuals with T2DM. This study evaluated the glycemic control-based cardiometabolic risk profiles of black Zimbabweans with T2DM. A cross-sectional study of 116 T2DM patients recruited from diabetic clinics at Parirenyatwa and Sally Mugabe Hospitals, Harare, Zimbabwe, was conducted. Blood samples were collected for glycated hemoglobin (HbA1c) and lipid profile assessment. The Framingham risk scores (FRS) based on body mass index (BMI) and lipid profile were used to determine CVD risk. Parametric variables were analyzed using one-way analysis of variance (ANOVA) with post hoc Bonferroni correction, while non-parametric variables were compared using the Kruskal-Wallis test with post hoc Dunn test for multiple comparisons. The overall frequency of dyslipidemia was 83.6% (n=97) and hypoalphalipoproteinemia was the most prevalent dyslipidemia (79.3%). Median HDLC levels were significantly lower in participants with poor glycemic control (1.12 mmol/L) compared to those with good glycemic control group (1.37 mmol/L) (p=0.011). Despite lack of significant variations in Framingham Risk Scores, there was a trend towards lower FRS-BMI in the good control group (29.8%) compared to the inadequate control (35.4%) and poor control (32.7%) groups (p=0.078). Duration since DM diagnosis was observed to be an important risk factor for poor glycemic control being significantly shorter in those with good glycemic control compared to those with inadequate and poor control. Overall, there was no significant difference in HbA1c status by age but individuals with poor glycemic control were significantly older than those with good control. The most prevalent dyslipidemia among the study participants was hypoalphalipoproteinemia which is reportedly associated with genetic predisposition, warranting further investigations.

Reirradiation in head and neck squamous cell carcinoma; prognostic indicators, oncologic and functional outcomes

ObjectivesPatients with recurrent squamous cell carcinoma of the head and neck (HNSCC) have a poor prognosis and limited therapeutic alternatives. While reirradiation is feasible, it is usually associated with high treatment toxicity and is not yet considered the standard of care. Based on current NCCN guidelines, in the context of very advanced head and neck cancer (recurrent and/or persistent disease), surgical intervention is explored initially with/without adjuvants while unresectable disease is approached with radiation and/or systemic therapies. Specific and reliable prognostic indicators for both -oncologic and functional outcomes- have yet to be defined for this population. MethodsRetrospective chart review of 54 patients treated with reirradiation at a tertiary academic institution between January of 1998 and January of 2024. Only patients with non-metastatic recurrent, and second primary HNSCC were included in the series. Demographics, staging, radiation dose and technique, additional therapy, histopathologic variables, EORTC toxicity, pre- and post-treatment PEG/tracheotomy dependency and oncologic outcomes were retrieved. ResultsThe study cohort consisted of 54 patients (37 males, 17 females) with HNSCC, averaging 62.7 years in age. Initial tumors were locally advanced in over 42 % of cases, with 58 % being node-negative. The head and cutaneous regions (24.5 %) and tongue (20.8 %) were the most common tumor sites. Primary surgical resection and adjuvant radiation were performed in 47.2 % of cases, and concurrent chemotherapy was used in 40.7 %. Reirradiation was mainly for local or regional recurrence (88.9 %), often following salvage surgery (68.5 %), with a mean dose of 5623 Gy over 52.5 fractions. Positive surgical margins were present in 29.4 % of cases, and extracapsular spread in 59.5 %. No significant differences were found between the salvage surgery and definitive reirradiation groups except for tumor site (P = 0.022). Median follow-up was 52.6 months, with 27 deaths reported. Lymphovascular invasion was significantly correlated with overall survival (P = 0.017), while initial tumor T-stage and neck disease involvement were linked to local-regional control (P = 0.030 and P = 0.033, respectively). Reirradiation increased tracheotomy and PEG-tube dependency by 20 % (P = 0.011) and 23 % (P = 0.003), respectively. ConclusionsReirradiation is a feasible therapeutic alternative in recurrent head and neck SCC. Oncologic outcomes observed in this series compare favorably to most published reports. Complete response and perineural invasion were independent prognostic factors for survival and locoregional control. While no mortality directly associated with treatment was observed in this series, reirradiation had a significant impact in functional outcomes in terms of increased risk of tracheotomy and peg tube dependency. Further studies are required to define the role of this treatment in head and neck cancer.

Impact of Attendance to a Pharmacist-Managed Medication Adherence Clinic on Glycemic Control and Risk Factors for Non-Completion Among Persons with Type 2 Diabetes Mellitus in Selangor, Malaysia.

Diabetes mellitus (DM) is a chronic metabolic disorder affecting millions globally. Adherence to treatment is crucial for effective management. To compare clinical outcomes, specifically changes in haemoglobin A1c (HbA1c) and fasting blood sugar (FBS) levels, between DM patients who completed the pharmacist-managed Diabetes Medication Therapy Adherence Clinic (DMTAC) sessions and those who did not, and to identify risk factors associated with non-completion of DMTAC. This multicenter, retrospective study included patients with DM attending DMTAC at five Ministry of Health centers from January 2018 to December 2020. Patients were categorized based on their completion of DMTAC sessions: those who completed at least four sessions and those who did not as per DMTAC protocol. The changes in HbA1c and FBS levels between the groups were analyzed. Logistic regression was employed to identify risk factors for non-completion of DMTAC. A total of 198 patients were included, comprising 49% male with a mean age of 56.52, ±12.91 years. The complete group consisted of 49% (n=99) of the patients, while the did not complete group included 50.5% (n=100). A statistically significant reduction in FBS levels from initial to final measurements was observed in the complete group compared to the did not complete group (P=0.024). Female gender, higher education levels, and a longer duration since DM diagnosis were significantly associated with non-completion of DMTAC. Diabetic patients attending at least four DMTAC sessions showed potential improvements in FBS levels. To enhance attendance at DMTAC sessions, healthcare professionals should focus on patients identified with risk factors for non-completion of DMTAC.

Organizational and infrastructural risk factors for health care–associated Clostridioides difficile infections or methicillin-resistant Staphylococcus aureus in hospitals

This study explores the infrastructural and organizational risk factors for healthcare-associated (HCA) Clostridioides difficile infections (CDIs) and methicillin-resistant Staphylococcus aureus (MRSA) in hospitals. This is a retrospective observational study involving all eligible inpatient units from 12 hospitals in British Columbia, Canada, from April 1, 2020 to September 16, 2021. The outcomes were the average HCA CDI or MRSA rates. Covariates included, but were not limited to, infection control factors (eg, hand hygiene rate), infrastructural factors (eg, unit age), and organizational factors (eg, hallway bed utilization). Multivariable regression was performed to identify statistically significant risk factors. Older units were associated with higher HCA CDI rates (adjusted relative risk [aRR]: 0.012; 95%confidence interval (CI) [0.004, 0.020]). Higher HCA MRSA rates were associated with decreased hand hygiene rate (aRR: -0.035; 95%CI [-0.063, -0.008]), higher MRSA bioburden (aRR: 9.008; 95%CI [5.586, 12.429]), increased utilization of hallway beds (aRR: 0.680; 95%CI [0.094, 1.267]), increased nursing overtime rate (aRR: 5.018; 95%CI [1.210, 8.826]), and not keeping the clean supply room door closed (aRR: -0.283; 95%CI [-0.536, -0.03]). The study confirmed the multifaceted nature of infection prevention and emphasized the importance of interdepartmental collaboration to improve patient safety.

Cooperation dynamics of prisoner's dilemma games on an evolutionary weighted network with heterogeneous preferences.

Relationships between people in real life are dynamically changed with the interaction process, and due to the heterogeneous preferences, this change is different from person to person. Based on this observation, we propose a new spatial and weighted prisoner's dilemma game model with heterogeneous individuals. Two types of tags, namely, tag-F (concerned about social fairness) and tag-W (concerned about personal well-being), are introduced to describe individuals' different preferences. The link weights indicating the interaction strength between individuals are updated based on different rules that depend on their tags. Through simulations, we verify that a large link weight control factor and a high proportion of tag-F individuals favor the emergence and persistence of cooperation. In addition, an increase in the link weight sensitivity factor favors the evolution of cooperation when the link weight control factor is small. Moreover, while the level of cooperation increases with the proportion of tag-F type in the population, contrary to our intuition, when the population consists entirely of tag-F individuals, in some cases, cooperation cannot reach a higher level compared with the situation when they are mixed with tag-W type. However, at high dilemma intensities, cooperators emerge only when the entire population consists of tag-F type. These results may provide some new insights into the impact of the evolutionary weighted network with heterogeneous preferences on collective cooperative behavior.

Advancing Metallic Lithium Anodes: A Review of Interface Design, Electrolyte Innovation, and Performance Enhancement Strategies.

Lithium (Li) metal is one of the most promising anode materials for next-generation, high-energy, Li-based batteries due to its exceptionally high specific capacity and low reduction potential. Nonetheless, intrinsic challenges such as detrimental interfacial reactions, significant volume expansion, and dendritic growth present considerable obstacles to its practical application. This review comprehensively summarizes various recent strategies for the modification and protection of metallic lithium anodes, offering insight into the latest advancements in electrode enhancement, electrolyte innovation, and interfacial design, as well as theoretical simulations related to the above. One notable trend is the optimization of electrolytes to suppress dendrite formation and enhance the stability of the electrode-electrolyte interface. This has been achieved through the development of new electrolytes with higher ionic conductivity and better compatibility with Li metal. Furthermore, significant progress has been made in the design and synthesis of novel Li metal composite anodes. These composite anodes, incorporating various additives such as polymers, ceramic particles, and carbon nanotubes, exhibit improved cycling stability and safety compared to pure Li metal. Research has used simulation computing, machine learning, and other methods to achieve electrochemical mechanics modeling and multi-field simulation in order to analyze and predict non-uniform lithium deposition processes and control factors. In-depth investigations into the electrochemical reactions, interfacial chemistry, and physical properties of these electrodes have provided valuable insights into their design and optimization. It systematically encapsulates the state-of-the-art developments in anode protection and delineates prospective trajectories for the technology's industrial evolution. This review aims to provide a detailed overview of the latest strategies for enhancing metallic lithium anodes in lithium-ion batteries, addressing the primary challenges and suggesting future directions for industrial advancement.

Unveiling the Psychological Consequences of Illness Perception in Pediatric Multiple Sclerosis: A Parent-Child Study.

Previous research has emphasized the significant role of illness perception in chronic diseases, including Multiple Sclerosis. Limited research has been conducted on exploring illness perception in Pediatric Onset Multiple Sclerosis (POMS), parental illness perception, and the impact of differences in their illness perceptions on the emotional well-being of the child. This study included 65 dyads of children aged 10-17 and their parents, divided into the following two groups: (I) 32 dyads of children with POMS and their parents; and (II) 33 dyads of healthy children and their parents. Overall, 73.1% and 43.8% of the children with POMS met the criteria for probable anxiety and depression, respectively, compared to 27.3% and 0% of the healthy children. Differences were found between the dimensions of illness perception in the POMS children and their parents, in the areas of consequences, personal control, identity, and control factors. Multinomial Logistic Regression indicated that differences in child-parent illness perception increased the likelihood of comorbid anxiety and depression by 37%. These findings underscore the importance of alignment between children with POMS and their parents in illness perception. Healthcare providers should prioritize interventions that address illness perceptions and be mindful of the potential impact on depression and anxiety comorbidity.

Effect of Grinding Conditions on Clinker Grinding Efficiency: Ball Size, Mill Rotation Speed, and Feed Rate

The production of cement, an essential material in civil engineering, requires a substantial energy input, with a significant portion of this energy consumed during the grinding stage. This study addresses the gap in the literature concerning the collective impact of key parameters, including ball size, feed rate, and mill speed, on grinding efficiency. Nine spherical balls, ranging from 15–65 mm, were utilized in six distinct distributions, alongside varying feed rates and mill speeds. ANOVA, Taguchi, and regression analyses were employed to explore their influence on grinding efficiency and cement properties. The findings revealed that ball size variation significantly affects grinding performance, with smaller diameter balls yielding higher efficiency due to increased abrasion and fine formation. Conversely, elevating mill speed generally diminishes grinding efficiency, particularly at speeds approaching 90% of the critical speed, impacting ball shoulder and foot angles. Moreover, increasing the feed rate affects the grinding performance differently based on ball distribution, with finer distributions experiencing adverse effects. Signal-to-noise ratios facilitated determining the optimal control factor levels to minimize energy consumption. Quadratic regression models exhibited strong predictive capabilities for energy consumption in grinding. Ultimately, the optimal grinding performance was achieved with Bond-type ball distribution No. 6, considering ball size, mill speed, and feed-rate interactions, albeit with considerations regarding grinding time and energy efficiency.

Utilizing Machine Learning Algorithms for the Development of Gully Erosion Susceptibility Maps: Evidence from the Chotanagpur Plateau Region, India

Gully erosion is a serious environmental threat, compromising soil health, damaging agricultural lands, and destroying vital infrastructure. Pinpointing regions prone to gully erosion demands careful selection of an appropriate machine learning algorithm. This choice is crucial, as the complex interplay of various environmental factors contributing to gully formation requires a nuanced analytical approach. To develop the most accurate Gully Erosion Susceptibility Map (GESM) for India’s Raiboni River basin, researchers harnessed the power of two cutting-edge machine learning algorithm: Extreme Gradient Boosting (XGBoost) and Random Forest (RF). For a comprehensive analysis, this study integrated 24 potential control factors. We meticulously investigated a dataset of 200 samples, ensuring an even balance between non-gullied and gullied locations. To assess multicollinearity among the 24 variables, we employed two techniques: the Information Gain Ratio (IGR) test and Variance Inflation Factors (VIF). Elevation, land use, river proximity, and rainfall most influenced the basin’s GESM. Rigorous tests validated XGBoost and RF model performance. XGBoost surpassed RF (ROC 86% vs. 83.1%). Quantile classification yielded a GESM with five levels: very high to very low. Our findings reveal that roughly 12% of the basin area is severely affected by gully erosion. These findings underscore the critical need for targeted interventions in these highly susceptible areas. Furthermore, our analysis of gully characteristics unveiled a predominance of V-shaped gullies, likely in an active developmental stage, supported by an average Shape Index (SI) value of 0.26 and a mean Erosivness Index (EI) of 0.33. This research demonstrates the potential of machine learning to pinpoint areas susceptible to gully erosion. By providing these valuable insights, policymakers can make informed decisions regarding sustainable land management practices.

Stable isotopes reveal soil evaporation and its controlling factors in the Heihe River source area on the northeastern Qinghai-Tibetan Plateau

Study regionThe Heihe River source area in the Northeastern Qinghai-Tibetan Plateau, China. Study focusSoil evaporation, which is a key process in soil water loss, is influenced by various environmental factors. However, the identification of its main drivers on a large scale in alpine mountains remains challenging due to sampling constraints. This study examined the spatial distribution of soil evaporation and control factors during the growing season in the Heihe River source area. New hydrological insightsThe results indicated that soil evaporation, represented by lc-excess values, gradually increased from southeast to northwest, and then decreased, reaching a depth of 50 cm below the surface. Although the normalized difference vegetation index explained 54 % of the spatial variation in soil evaporation, the interaction between land surface temperature and soil water content (SWC) provided a more robust explanation. The soil evaporation losses exhibited the following pattern: cropland > grassland > forest land > shrubland. In forest land and shrubland, SWC and precipitation explained 68 % and 73.3 % of the spatial variations in soil evaporation, respectively. Grassland mainly relied on temperature and SWC, with 49.33 % of unexplained spatial variability by environmental factors. Meanwhile, the aridity index and aspect explained 45 % and 44.6 % of the spatial variations in cropland. These findings provided invaluable information for advancing our understanding of the ecohydrological processes in alpine mountains.

Risk assessment of infection of COVID-19 contacts based on scenario simulation.

We constructed a rapid infection risk assessment model for contacts of COVID-19. The improved Wells-Riley model was used to estimate the probability of infection for contacts of COVID-19 in the same place and evaluate their risk grades. We used COVID-19 outbreaks that were documented to validate the accuracy of the model. We analyzed the relationship between controllable factors and infection probability and constructed common scenarios to analyze the infection risk of contacts in different scenarios. The model showed the robustness of the fitting (mean relative error = 5.89%, mean absolute error = 2.03%, root mean squared error = 2.03%, R2 = 0.991). We found that improving ventilation from poorly ventilated to naturally ventilated and wearing masks can reduce the probability of infection by about two times. Contacts in places of light activity, loud talking or singing, and heavy exercise, oral breathing (e.g., gyms, KTV, choirs) were at higher risk of infection. The model constructed in this study can quickly and accurately assess the infection risk grades of COVID-19 contacts. Simply opening doors and windows for ventilation can significantly reduce the risk of infection in certain places. The places of light activity, loud talking or singing, and heavy exercise, oral breathing, should pay more attention to prevent and control transmission of the epidemic.

Analysis of Ovality Deviation of Bending Superheater Tube Boiler Fabrication Process with Six Sigma Method in Manufacturing Company

Quality control in fabrication is critical to the success of the production process. In this study, key factors in production quality control were identified by analyzing the influence on the tube bending process in fabrication work. Ovality deviations occur during the tube bending process that exceeds 9 percent. 30 boiler superheater tube elements had to go through the repair process. The causes of tube bending deviations were analyzed using the Six Sigma approach with the DMAIC (Define, Measure, Analyze, Improve, and Control) methodology. The causes of failure were analyzed using FMEA, and the highest RPN of 320 was obtained due to design planning and manufacturing of bending dies that are in accordance with the OD tube and the placement of clamp die and pressure die distances that are not too far apart. In addition, an RPN value of 294 was obtained due to the bending speed being too high. The recommendation for the next project is to consider using a C-Frame machine with better control to make it easier for operators to adjust the pressure, temperature, and speed of a good machine to better maintain ovality.

Geochemistry of Middle Jurassic Coals from the Dananhu Mine, Xinjiang: Emphasis on Sediment Source and Control Factors of Critical Metals

In recent years, coal-type critical metal deposits have become a research hotspot in coal geology. As a major coal-accumulating basin in the Xinjiang area, the Turpan-Hami Basin contains abundant coal resources and has the potential to become a large coal-type critical metal deposit. However, previous studies on the enrichment characteristics of critical metal elements in coal are few and need further research. Based on SEM-EDS, XRF, and ICP-MS experiments, this study investigates the coal petrology, mineralogy, and geochemistry of the No. 22 coal of the Xishanyao Formation from the Dananhu Coal Mine, Xinjiang, to identify the sediment source, depositional environment, and controlling factors of the critical metal elements of the No. 22 coal. The results showed that the Dananhu coals are characterized by a low ash yield, low total sulfur content, high volatile yield, and high inertinite proportions. Quartz, kaolinite, and illite are the main minerals in the coal. Compared with the world’s low-rank coals, Ni, Co, Mo, and Ta are slightly enriched, Li, Rb, Cs, Ba, Tl, Bi, and Ge are depleted, and the concentrations of other trace elements are comparable to the average values of the world’s low-rank coals. The REY of the Dannanhu coals exhibited high fractionation, with its enrichment patterns characterized by the H-type and M-H-type. Although most of the critical metals are not enriched in the Dannanhu coals, the Ga, Zr (Hf), and Nb (Ta) concentrations in the coal ash of the Dannanhu coals have reached the economic cut-off grade and have the potential to be a substitute for rare metal resources. The terrigenous detrital sources of the Dannanhu coals mainly come from the Paleozoic dacite, andesite, and a small amount of granite from the Harik Mountain and Eastern Bogda Mountain in the Turpan-Hami Basin. The Dannanhu coals are generally in a dry and hot depositional environment, with high salinity and weak reduction-oxidation. The low source input and weak reduction-oxidation environment have resulted in low concentrations of critical metal of the No. 22 coal from the Dananhu Coal Mine.