Face Width Research Articles

Computed tomography assessment of neurocranial structures for sexual dimorphism identification: a meta-analysis.

The human neurocranium exhibits significant sexual dimorphism, making it a valuable resource for anthropological studies. This systematic review aggregated and analyzed data from literature on sex differences in neurocranial dimensions as measured by computed tomography (CT). Following registration of the review protocol with PROSPERO (#CRD 42023442451), comprehensive searches were conducted in six databases and gray literature. From an initial pool of 1,499 articles, 14 met the inclusion criteria and were analyzed for data extraction, meta-analysis of linear measurements, risk of bias (RoB), and certainty of evidence (GRADE) evaluation. In the meta-analysis (Sample size- 1726 female and 1837 male), the inverse variance method and a random-effects model were employed using Review Manager (version 5.4.1). Statistical heterogeneity was quantified using the I2 coefficient. The studies primarily involved linear measurements between specific cranial landmarks, manually delineated using imaging software. Measurements analyzed included Maximum Cranial Length (G-Op), Cranial Base Length (N-Ba and N-Pfm), Cranial Height (Ba-Br), Frontal Chord (N-Br), Maximum Cranial Breadth (Eu-Eu), Minimum Frontal Breadth (Ft-Ft), Upper Facial Breadth (Fmt-Fmt), and Bimastoid Breadth (Ms-Ms). Results indicated that the mean values were significantly lower in females (p < 0.001), with no differences between the subgroups of dry skulls and living patients. The largest differences between sexes were observed in G-Op [-8.64 (-9.69, -7.59) mm] and N-Pfm [-8.83mm (-12.75, -4.91)]. Our meta-analysis showed a low risk of bias, and measurements of N-Ba, Ba-Br, N-Br, and Ms-Ms demonstrated high certainty of evidence according to the GRADE approach. This research underscores the reliability of specific neurocranial measurements for sex differentiation in CT scans, with smaller dimensions consistently found in females.

3D Assessment of Mandibular Margin Morphological Change after BTX-A Injection for Masseter Hypertrophy: A Retrospective Study.

Some facial morphological changes may occur in some patients after botulinum toxin A (BTX-A) injection for the treatment of masseteric hypertrophy. The aim of this study was to investigate the morphological changes that occurred on mandibular margin. This retrospective analysis included 43 patients (86 lateral cases) who received BTX-A injections for masseter hypertrophy. To assess the morphological changes in the mandibular margin after treatment, the sharpness of the mandibular margin was evaluated before and after the injections using an established grading system. Additionally, 3D scanning technology was used to measure both the therapeutic effect of the BTX-A injections and the extent of soft tissue sagging in the mandibular margin area. Grading: The grade of mandibular margin sharpness change occurred in 41 lateral cases post-procedurally. Based on the measurement results, statistically significant differences were observed before, 1 month, and 3 months post-procedurally in subjects' positive lower face width representing the therapeutic effect of BTX-A injection and the extent of sagging soft tissue at sagittal section B and section C (p < 0.05), but not in section A (A: outer canthus, B: midpoint of the eyelid margin, and C: inner canthus) (p > 0.05). After receiving a BTX-A injection for masseteric hypertrophy, the mandibular margin may develop an unclear mandibular margin and sagging soft tissue in mandibular margin area. EBM Level: IV LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Determining the Best Design Factors of a Two-stage Helical Gearbox with Two Gear Sets in the First Stage to Increase Efficiency and Reduce Volume using the SAW Method

This study describes the outcomes of employing the Simple Additive Weighting (SAW) approach to address the Multi-Objective Optimization Problem (MOOP) of a two-stage helical gearbox with two gear sets at the first stage. Its objective is to determine the key design variables that can reduce the volume of the gearbox while simultaneously maximizing its efficiency. For this investigation, three key design parameters were selected, namely the coefficients of the wheel face width of the first and second stages (Xba1 and Xba2), and the gear ratio of the first stage u1. In addition, the SAW technique was deployed to deal with the problem of Multi-Criteria Decision Making (MCDM), while the Method based on the Removal Effects of Criteria (MEREC) was employed to determine the weight criterion for addressing the MOOP. The obtained results are valuable for defining the optimal values for three primary design factors, which are essential for the development of a two-stage helical gearbox with two gear sets at the first stage.

Multi-Objective Optimization of a Two-stage Helical Gearbox with Double Gears in the First Stage using MARCOS

This study demonstrates the solution of the Multi-Objective Optimization Problem (MOOP) of a two-stage helical gearbox with double gears at the first stage, following the MARCOS methodology. The goal of this work is to identify the most effective essential design factors to reduce the bottom area of the gearbox while maximizing its efficiency, which constituted a significant novel finding. For this purpose, three crucial design parameters were selected, the first stage gear ratio and the wheel face width (Xba) coefficients for the first and second stage. Furthermore, the Multi-Criteria Decision Making (MCDM) issue was chosen to be handled by the MARCOS method, and the weight criterion for solving the MOOP was determined by the MEREC method. The drawn conclusions are useful in developing a two-stage helical gearbox with double gears at the first stage by helping to identify the ideal values for the three important design parameters.

Prevalence of malocclusion and craniofacial morphological variations among 7-13-year-old children in Elementary School, Kediri

Background: Craniofacial morphological variations can influence malocclusion. Mesocephalic head tends to form mesoprosopic face and class I malocclusion. Dolicocephalic head tends to form leptoprosopic face and class II malocclusion. Brachycephalic head tends to form euryprosopic face and class III malocclusion. Emphasizing the importance of malocclusion early treatment, research on malocclusion prevalence and craniofacial morphology variations in growing children is needed. Purpose: To determine malocclusion prevalence and craniofacial morphological variations among 7-13-year-old children at Medowo III Elementary School, Kediri. Methods: This descriptive study used 44 samples of Medowo III Elementary School, Kediri students. Head and face length and width were measured using a spreading caliper. The cephalic and facial indices were then determined for the classification of head and facial types. Results: The dominant craniofacial morphological variations in the samples were hyper-brachycephalic head (39 samples) and euryprosopic face (14 samples). The highest prevalence of malocclusion among individuals with hyper-brachycephalic head type was Angle’s class I malocclusion. Class II malocclusion was found in 1 sample, and class III malocclusion in 3 samples. Among the samples with this head type, the most common malocclusion variations were anterior crowding (36 samples), followed by deep bite (15 samples). Conclusion: The highest prevalence of malocclusion among Medowo III Elementary School, Kediri students was Angle class I malocclusion, characterized by specific craniofacial morphological variations, namely hyper-brachycephalic head type and euryprosopic face.

Relative facial width, and its association with canine size and body mass among chimpanzees and bonobos: Implications for understanding facial width-to-height ratio expression among human populations.

Facial width-to-height ratio (fWHR) has been widely investigated in the context of its role in visual communication, though there is a lack of consensus about how fWHR serves as a social signal. To better understand fWHR variation in a comparative context, we investigate the associations between fWHR and canine crown height (CCH) and body mass, respectively, among two chimpanzee subspecies (Pan troglodytes schweinfurthii, Pan troglodytes troglodytes) and bonobos (Pan paniscus). We collected landmark data from 3D surface models of 86 Pan cranial specimens to quantify fWHR and upper CCH, and to estimate body mass. We used Spearman's r and Kruskal-Wallis tests to test for significant relationships among variables, and to assess sexual dimorphism. There is an inverse relationship between fWHR and CCH in both sexes of Pan, however there are interpopulation differences in the relationship between fWHR and CCH among Pan taxa. Pan paniscus have relatively wide faces and small canine crowns, and wide faces in Pan t. schweinfurthii males may be driven by body size constraints. Pan troglodytes and Pan paniscus show fWHR dimorphism, and Pan paniscus have significantly higher fWHRs than do either Pan troglodytes subspecies. Our findings indicate that CCH and facial breadth may serve subtly different signaling functions among Pan taxa. Further research into the circumstances in which wide faces evolved among chimpanzees and bonobos will likely afford deeper insights into the function of relatively wide faces in the context of visual signaling among humans and our extinct hominin relatives.

Determining of the relationship between gum phenotype and anthropometric data of the face and gender

Relevance. Diagnosis of the condition of periodontal tissues at the stage of comprehensive treatment planning for a dental patient is an important step in the work of dentists. The presence of difficulties in diagnosing the phenotypic condition of the gums dictates the need to search for additional clinical diagnostic methods that allow determining the phenotype with minimal time and financial costs.Objective. To determine the relationship between anthropometric values of the face (width and height of the face) and gender with the gin-gival phenotype.Materials and methods. During the clinical examinations, an analysis was carried out of the anthropometric data of men and women obtained as a result of photometry, the results of a study of the gingival phenotype by transgingival probing using the De Rouck method and CBCT data (cone beam computed tomography) in patients with their further distribution into groups. A total of 45 people took part in the study, of which 12 were men and 33 were women.Results. Statistical processing of the obtained data showed that for men, the differences between the groups with different phenotypes (thick/ thin) are reliable for the parameter face width. For women with different gum phenotypes (thick and thin), reliable differences were obtained between the groups for the parameters face height and face width. The gum phenotype correlates with the face width (noticeable correlation for all, high for men and women separately); face height (moderate correlation for all, men and women); but does not correlate with the facial index and gender.Conclusion. Thus, the study showed that a combined diagnostic examination of the patient, taking into account gender, facial height and width in women, and facial width in men, can help in the correct assessment of the gingival phenotype.

The application of basic SMAS rhytidectomy and comprehensive SMAS rhytidectomy.

Rhytidectomy has made great progress in the past 50 years, especially after the proposition of the concept of superficial musculoaponeurotic system (SMAS). Our previous research had classified SMAS rhytidectomy into basic SMAS rhytidectomy (B-SMAS) and comprehensive SMAS rhytidectomy (C-SMAS) according to whether the treatment of SMAS aponeurosis is combined with retaining ligament, fat pad, mimetic muscles, etc. The purpose of this paper is to compare the outcomes of the 2 methods. Through multicenter collaborative research, 21 cases of B-SMAS and 18 cases of C-SMAS were collected. Photographs were taken pre- and post-operation for each patient, and the facial width of the lateral canthus level (upper face), the alar base level (middle face), and the oral commissure level (lower face) were measured. We compared the statistics of upper, middle, and lower face pre- and post-B-SMAS and C-SMAS to assess the ramifications of each operation. We used preoperative measurements minus corresponding postoperative measurements of specific operation to assess which position would acquire superior improvements. We also recruited 3 professional plastic clinicians to rate the ramifications of specific positions and approaches after pre- and post-photo comparing. Through comprehensive analyzing, we compared the improvements between B-SMAS and C-SMAS to assess which method is more beneficial concerning facial rejuvenation. Both B-SMAS and C-SMAS would acquire optimal changing concerning facial width in middle and lower face after operation (P < .05). Two methods all harvested better width changing effects in middle and lower face than upper face (P < .05). However, C-SMAS acquired better effects in middle and lower face than B-SMAS (P < .05). Both B-SMAS and C-SMAS are beneficial to facial rejuvenation. The effects in middle and lower face are better than upper face. In addition, C-SMAS may be more effective than B-SMAS.

The Periarticular Pelvic Clamp: An Indispensable Aid to Assist in the Narrowing of Facial Width in Mandibular Trauma.

Symphyseal fractures of the mandible with concomitant bilateral condylar fractures can often be a particularly challenging fracture pattern for the facial surgeon. Improper reduction of these fractures may lead to facial widening that proves difficult to correct secondarily. Here the authors describe a method to prevent this unwanted facial widening with the use of an orthopedic periarticular reduction clamp. This method allows for not only increased ease of reduction but also reduces the burden of assistance in manual reduction of the fracture.

Comparisons of the Clinical Outcomes of Mandible Contouring Surgery With or Without the Use of Intraoral Drains.

Mandible contouring surgery is a common cosmetic procedure aimed at reducing the width of the lower face or correcting chin-related issues by contouring the mandible. Typically, an intraoral drain is placed during procedures involving the reduction of the mandible angle portion to mitigate seroma or hematoma formation. Despite this standard practice, anecdotal evidence suggests that the omission of drains does not significantly impact complication rates or surgical outcomes. A retrospective study was conducted to compare surgical outcomes and complication rates between patients who received intraoral drains (n = 338) and those who did not (n = 132) during mandible contouring surgery. The primary outcomes measured included the incidence of seroma, hematoma, and infection by counting the number of post-operative interventions required to address these complications. Statistical analysis was performed using chi-square tests for categorical variables. A p-value of < 0.05 was considered statistically significant. The incidence of post-operative surgical interventions for bleeding control or hematoma evacuation in the drain group was 0.59% compared to 0% in the no-drain group (p = 0.922). Minimally invasive interventions were required in 2.37% of patients with drains and 3.03% without drains (p = 0.933). Infection rates were 1.18% in the drain group versus 0.76% in the no-drain group (p = 1.0). The study demonstrates no statistically significant difference in complication rates between mandible contouring surgeries performed with or without intraoral drains. These findings suggest that the routine use of drains may be unnecessary, potentially simplifying post-operative care and reducing patient discomfort. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Beauty Re-defined: A Comparative Analysis of Artificial Intelligence-Generated Ideals and Traditional Standards.

Background Traditional methods for assessing facial beauty rely on subjective measures like averages or "golden ratios." However, artificial intelligence (AI) offers a data-driven approach to analyzing attractiveness. This study explores how AI-generated beauty criteria compare to established ideals, considering cultural influences and the evolving concept of beauty. Methods To explore how AI-generated beauty ideals compare to traditional standards, we used three AI text-to-image generation tools (Dezgo (Dezgo SAS LLC, France), Freepik (FreePik Company, Malaga, Spain), and ImagineArt (Vyro, Islamabad, Pakistan)) to create images from a specific prompt. The first four generated images for each gender that met our criteria were included in this study. A single researcher used MediaPipe Studio software to identify ten key facial landmarks on each image. Landmark distances were measured twice in Adobe Photoshop 2023 (Adobe, San Jose, California, United States) and averaged for each measurement. The average values were then used to calculate 23 facial proportion ratios based on established neoclassical canons and golden facial ratios. We then compared these AI-generated ratios to the ideal values using one-sample t-tests in IBM SPSS Statistics for Windows, Version 29 (Released 2023; IBM Corp., Armonk, New York, United States), p < 0.05 significance, to assess alignment with traditional beauty standards. Results AI-generated faces displayed statistically significant differences, p < 0.05, from established beauty standards in both neoclassical canons and golden ratios for both males and females. Differences were seen in facial width, upper and lower face proportions, and eye symmetry. Conclusion AI-generated faces deviated from traditional beauty standards of neoclassical canons and golden ratios for both genders. This suggests AI incorporates factors beyond established ideals, potentially reflecting contemporary preferences, cultural biases, or emerging trends.

Simulation Research on the Control Method of Bow-Collapse in Gear Cold Roll-Beating

Bow-collapse is a type of geometric defect in the gear cold roll-beating process. In order to effectively control bow-collapse and improve material utilization, this paper calculates the cross-section radius of the blank according to the volume invariance principle of metal plastic deformation, and then performs FE simulation of the cold roll-beating process by using the cyclic beating of adjacent tooth spaces and intermittent blank feeding method. The flow state of metal particles is investigated, revealing that the movement of metal particles along the axial direction of the blank is the main reason for the formation of bow-collapse. This paper proposes a method to correct the cross-section radius of the blank and thus control for bow-collapse, where the loss coefficient K characterizes the state of metal particle loss in an infinitesimal thickness region on the cross-section. The analytical equation for calculating the corrected value of the cross-section radius is derived, and the corrected value is calculated. Conducted on the modified blank, cold roll-beating FE simulation results show that bow-collapse is effectively controlled, and the loss coefficient K correctly reflects the loss state of metal particles on the cross-section. The simulation results also show that after cold roll-beating, the gear teeth with standard face width and tooth depth can be obtained after two turning end faces and turning tip circle processes. The bow-collapse control method proposed in this paper effectively improves material utilization.

Gender dimorphism of the relationships between the cranial and facial skull sections in mature human individuals

Background. To date, the range of individual anatomical variability of the cranial profile type in mature adults, depending on gender and skull structure type has not yet been adequately established. Aim. To study gender-specific ratios of the cranial and facial parts of the skull in mature adults. Materials and Methods. The materials of our study consisted of 115 skulls of mature adults of both sexes, including 35 dry bone specimens of whole or fragmented skulls. For each parameter, the following metrics were calculated: The following parameters were used in the statistical analysis: (arithmetic mean), σ (standard deviation), and m (standard error of the mean). Results. It was found that in men the skull length is =181.36 with σ=3.31 and m=0.46, while in women it does not exceed =176.57 with σ=3.28 and m=0.47; the skull width in men reaches =141.17 with σ=2.62 and m=0.34, and in women, it does not exceed =134.94 with σ=2.50 and m=0.33; the height parameter of the skull in men also reaches maximum values at the level of =141.38 with σ=3.75 and m=0.52, while in women, it is somewhat lower at =137.24 with σ=3.15 and m=0.55. In mature men, the upper facial width is =94.17 with σ=3.87 and m=0.50, while in women, this parameter averages =90.71 with σ=4.05 and m=0.54; the middle width in men reaches =128.93 with σ=1.53 and m=0.20, while in women, it does not exceed =122.49 with σ=1.44 and m=0.19; the maximum indicators of angular width are established in men, averaging =99.64 with σ=4.15 and m=0.54, while in women, they do not exceed =92.27 with σ=3.78 and m=0.51. Conclusions. The study identified significant gender-specific differences in the cranial and facial dimensions of middle-aged individuals. Men demonstrated larger average values for skull length, width, and height, as well as upper face width, bizygomatic width, and angular width, compared to women. These findings highlight distinct morphological characteristics between genders. Keywords: computed tomography, cranial index, face width, face length, face height.

Effects of Tool Shape on Facial Contour Reduction in Middle-aged Women in Their 50s and 60s

Purpose: This study aimed to evaluate the effect of tool-based facial care on face size reduction in middle-aged women and to analyze the differences in effectiveness by tool form.Methods: The study was conducted with 14 middle-aged women in their 50s and 60s who volunteered to participate at a P aesthetic shop in Gangnam-gu, Seoul. The participants were divided into three groups: Group A (11 participants) received treatment with a meridian-scraping-shaped tool, Group B (4 participants) received treatment with a plain tool, and Group C (3 participants) was untreated. Group A underwent treatment twice a week for a total of six sessions with the meridian-scraping-shaped tool. After a year, some participants from Group A were reassigned to Group B for further care with the plain tool. Face sizes were compared over time by measuring 14 variables, including length, width, and jawline length. Data were analyzed using Kruskal–Wallis and Friedman tests.Results: In Group A, there was a significant reduction in most facial areas, particularly in face width and jaw width (p&lt;0.001). In contrast, Group B showed significant reductions in only some areas, while no changes were observed in the control group. This study found that the meridian-scraping-shaped tool was more effective in reducing facial contours than the plain tool.Conclusion: This study demonstrated that the meridian-scraping-shaped tool, which applies the leverage principle, was more effective in reducing facial contours in middle-aged women compared to the plain tool. The shape of the tool has a critical impact on treatment outcomes.

Creative puppet therapy reduces hallucinations in patients diagnosed with schizophrenia: Preliminary findings

Anomalous experiences and hallucinations characterize schizophrenia. This study aimed at determining the efficacy of creative puppet therapy (CPT; creation of a puppet with malleable DAS) to reduce severe anomalous experiences and hallucinations among patients diagnosed with schizophrenia. Double-blinded, controlled trials were performed on a convenience sample of 24 patients from a mental health center. The intervention group of 12 patients (who created puppets) and the pseudo-treatment group of 12 patients (who were involved in outdoor leisure trips) were compared to the control group of 12 control participants (who created puppets). Cardiff Anomalous Perceptions Scale (CAPS) assessed hallucinations; Emotional Expression Inventory (EEXI) assessed the emotional expression of one's own puppet. Puppet facial features were measured. Results showed that CPT effectively reduced (d = –4.00) hallucination frequency in patients. Hallucination reduction occurred across all sensory modalities, but touch and bodily interoception. Exteroceptive vs. interoceptive hallucinations was the most valuable classification in patients. Compared to controls, puppets created by patients expressed more negative emotions and had larger eye diameters, shorter noses, and larger whole face width. Eye diameter was correlated with fear, sadness, anger, and disgust, and whole face width with boredom. Fragmented-self integration of schizophrenia through CPT treatment might exploit aggregative dominance of the patient's own body.

A clinical prospective study on the surgical management of zygomatico-maxillary complex fractures using two-point fixation

The ZMC fractures are one of the most frequently occurring maxillofacial injuries due to its prominence and facial contour. The ZMC forms a principle buttress of face and helps transmit occlusal forces to skull base. Fracture of zygomatic bone leads aesthetic and functional deformity. Restoration to premorbid condition is most predictable by ORIF. In this study was to evaluate efficacy of two-point internal fixation using conventional miniplates and screws for ZMC fractures. 35 patients with established unilateral isolated ZMC fractures were operated using two-point fixation method i.e. the maxillary buttress and the fronto-zygomatic suture, followed up for 3 months. Patients were assessed clinically and radiographically at different follow up intervals. Charts of patients were reviewed for age, gender, etiology, malar height analysis and vertical dystopia. 35 patients in this study, underwent ORIF under GA with two-point fixation. Preoperatively, mean malar height of the patients recorded was 66.55 ± 3.02. There was a significant increase in malar height postoperatively (P &amp;#60; 0.0001). 70.24 ± 2.05, at 1st week, and 69.87 ± 1.98. in 3rd and 6th weeks. Preoperatively, mean vertical dystopia of patients was 2.24 ± 0.71. Postoperative resolution of vertical dystopia was statistically significant (P&amp;#60;0.0001), with value of 0.52 ± 0.52.Integrity of ZMC is important in maintenance of normal facial width and prominence of cheek. Two‑point fixation shows satisfactory results functionally, esthetically and also provides additional advantage by eliminating another surgical site. Thus we conclude that our study provides a basis for further research.

Polymer gear failure prediction: A regression-Based approach using FEA and photoelasticity technique

The research aims to develop a model to predict the maximum contact stress depth, which will be correlated with polymer gear failures such as wear and rapid thermal deformation. A thorough 3D Finite Element Analysis (FEA) was performed for different gear parameters (varying module, number of teeth, and face width) in different combinations (Polymer – Polymer, Steel – Polymer, and Polymer – Steel). The simulation results showed that the contact stress depth increases with respect to the module and number of teeth; meanwhile, very negligible variations were found along the face width. Also, the findings indicate that the contact stress depth varied in the following descending combinations of gear pair: Polymer – Polymer, Steel – Polymer, and Polymer – Steel. The 3D FEA contact stress patterns were validated experimentally by utilizing the in-house developed photoelasticity test rig. The data obtained from the simulation results were used to develop regression models (Linear regression and Random Forest regressor) for estimating the maximum contact stress depth. A feature importance study was done using the mean reduction of the Gini index or impurities in random forest. It was found that torque applied and contact width of the gear pair were significantly influenced by the contact stress depth. Finally, an equation was developed correlating torque and contact width to predict the depth occurrence of maximum contact stress through which the failure mode of the polymer gear could be predicted.

Craniometric determinants of the fitted filtration efficiency of disposable masks.

Exposure to harmful aerosols is of increasing public health concern due to the SARS-CoV-2 pandemic and wildland fires. These events have prompted risk reduction behaviors, notably the use of disposable respiratory protection. This project investigated whether craniofacial morphology impacts the efficiency of disposable masks (N95, KN95, surgical masks, KF94) most often worn by the public to protect against toxic and infectious aerosols. This project was registered with ClinicaltTrials.gov (NCT05388201; registration May 18, 2022). One-hundred participants (50 men, 50 women) visited the Environmental Protection Agency's Human Studies Facility in Chapel Hill, NC between 2022-2023. Craniometrics and 3D scans were used to separate participants into four clusters. Boosting and elastic net regression yielded five measurements (bizygomatic breadth, nose length, bizygomatic nasal arc, neck circumference, ear breadth) that were the best predictors of filtration efficiency based on overall model fit. Fitted filtration efficiency was quantified for each mask at baseline and when tightened using an ear-loop clip. The mean unmodified mask performance ranged from 55.3% (15.7%) in the large KF94 to 69.5% (12.3%) in the KN95. Modified performance ranged from 66.3% (9.4%) in the surgical to 80.7% (12.0%) in the KN95. Clusters with larger face width and neck circumference had higher unmodified mask efficiency. Larger nose gap area and nose length decreased modified mask performance. We identify face width, nose size, nose shape, neck circumference, and ear breadth as specific features that modulate disposable mask fit in both unmodified and modified conditions. This information can optimize guidance on respiratory protection afforded by disposable ear-loop masks.

The Design and Analysis of the Helical Gear in the Car Gear Box for the Slag Port Transfer

The design and analysis of helical gears with involutes profiles is the primary focus of this study. The most widely utilized gearing system in use today is the involutes gear profile. Power and torque are typically transmitted through them. When compared to other forms of transmission, the efficiency of power transmission via gears is extremely high. Bending and contact stress are the main causes of gear tooth failure. The current study examines helical gear, which has to do with slag transfer in the steel production sector. The most affected stress concentrated location of any set of gears in the slag port transfer car (SPTC) gear box is identified by examining the contact stresses for the current design set of gears. The high stress concentration gear set was redesigned with a constant (45mm) face width at various Helix angles (14, 15, 16, 17, 19^, 20 ̊, 25^, and 30 ̊) and a constant pressure angle (20). To calculate the contact stresses between two gears that are mating. The robust and cutting-edge solid modeling program AUTODESK FUSION 360 creates a three-dimensional solid model. The ANSYS Workbench module was utilized to do the numerical analysis. The outcomes of the workbench module for ANSYS. The current study is helpful in quantifying the previously mentioned factors, which aids in the safe and effective design of the helical gear in the SPTC Gearbox.

Research on the Development Height Prediction Model of Water-Conduction Fracture Zones under Conditions of Extremely Thin Coal Seam Mining

Addressing the difficult problem of predicting the height of water-conducting fracture zones in shallow and thin coal seams, a prediction model of water-conduction fracture zones based on a backpropagation (BP) neural network was developed by integrating theoretical analysis, field measurements, and algorithmic advancements. Firstly, through overburden migration analysis and correlation tests, the height index system of the water-conducting fracture zone was determined. This system includes mining height, buried depth, dip angle, working face width, and overburden rock lithology, with five groups of characteristic parameters. Then, 35 pairs of minefield-measured data were collected to establish the measured height data set of the water-conducting fracture zone. Secondly, a BP neural network prediction model and a traditional support vector regression (SVR) prediction model were constructed based on a Pytorch framework, and the models were trained and tested by selecting data sets. Thirdly, the optimal prediction model was determined by comparing the model with the empirical model and multiple regression model of mining regulations for coal pillar maintenance and pressure in buildings, water bodies, railways, and main shafts. Finally, a typical mine was selected for application to verify the suitability of the optimal model. The results show that: (1) the predicted value of the neural network model is consistent with the change trend of the measured value, which accords with the theoretical law; (2) compared with traditional forecasting methods, the error of the BP neural network prediction model is stable and the prediction effect is the best; (3) dropout can effectively mitigate mitigation training overfitting, achieve regularization, and improve prediction accuracy; (4) the field application further verified that the BP neural network model is the best for predicting the height of water-conducting fracture zones of extremely thin coal seams, and the research results can provide technical guidance for similar fragile coal seams.