Cavity Volume Research Articles

Simulating and Evaluating the Multiphase Jet Flow Characteristics of a Five‐Hole Oxygen Lance under Nonisothermal Conditions

The oxygen lance jet plays a crucial role in the steelmaking process in a converter. The quantitative relationship between the operating parameters of the oxygen lance and the volume of the impact cavity is established for the first time, and the leading factors affecting the volume of the impact cavity are identified through correlation analysis. This article examines the influence of operating pressure and lance position on the impact cavity of a 170 t converter in a nonisothermal environment through numerical analysis. The results show that the ambient temperature in the converter presents a layered phenomenon. The temperature near the free surface ranges from 1550 to 1600 K and then gradually decreases to 900 K at the oxygen lance outlet. When the ratio of the operating pressure to the design working pressure is less than 1.0 or greater than 1.3, the cavity volume is significantly affected by the operating pressure but has less of an impact when the ratio is between 1.0 and 1.3. The cavity volume shows a linear relationship with the oxygen lance position. Moreover, the oxygen lance position has a greater influence on the cavity volume and velocity distribution than do the operating pressure.

Modelling of chemical kinetics in the presence of hydrodynamic cavitation for wastewater treatment applications

The reaction rate of hydroxyl radicals with organic pollutants is about 108−1011 /mol-s, can degrade a wide range of pollutants. Intense bubble collapse during hydrodynamic cavitation can produce hydroxyl radicals, making it suitable for wastewater treatment. The current study introduces a numerical method of predicting the performance of a hydrodynamic cavitation reactor. Unlike most literature that considers cavitation volume as an indicator of effectiveness of hydrodynamic cavitation, the present approach considers local pressure variation, cavitation volume fluctuation, radical production and their inter-relations. The findings show that though an initial increase in the extent of cavitation, marked by a rise in cavity volume, leads to higher OH. radical production, the radical generation declines below an optimal cavitation number. The downstream recovery pressure also influences radical production. This numerical methodology, providing complete picture of radical production and its locations, will be very helpful for designing a new and more efficient cavitation reactor.

Correlation between oral cavity volume and upper airway changes in skeletal Class III patients undergoing bimaxillary orthognathic surgery: a pilot cone-beam computed tomography study.

To evaluate changes of the upper airway and oral cavity volumes in patients with skeletal Class III malocclusion undergoing bimaxillary orthognathic surgery, and to analyze the correlation between postoperative upper airway decrease and the amount of jaw movement and oral cavity volume reduction. Thirty patients (16 males and 14 females) undergoing bimaxillary surgery were included. Three-dimensional reconstruction of the upper airway and oral cavity were performed using preoperative (T0) and postoperative (T1) (6 months) cone-beam computed tomography scans. The volume, sagittal area and minimum cross-sectional area of the upper airway were diminished (P < .001). The decrease in volume and minimum cross-sectional area in the oropharyngeal region of the upper airway were weakly correlated with B-point posterior movement (P < .05). Total oral cavity volume was decreased, with maxillary oral volume increasing and mandibular oral volume decreasing (P < .001). Upper airway decrease was highly correlated with total oral volume reduction and mandibular oral volume reduction, with the most significant correlation being with total oral volume reduction (P < .001). Class III bimaxillary surgery reduced the volume, sagittal area, and minimum cross-sectional area of the upper airway as well as oral cavity volume. Upper airway changes were weakly correlated with anterior-posterior mandibular movement but significantly correlated with oral cavity volume changes. Thus, oral cavity volume reduction is a crucial factor of upper airway decrease in patients with skeletal Class III malocclusion undergoing bimaxillary orthognathic surgery.

Enhancing gas drainage efficiency in soft coal seams: Mechanically over-excavated cavities along borehole in floor tunnels

In addressing the challenge of gas drainage in soft coal seams, this study introduces an innovative technique involving mechanically over-excavated cavities along boreholes in floor tunnels. Through a combination of laboratory experiments, numerical simulations, and field tests, we investigate the efficacy of this method in weakening the coal structure and enhancing gas extraction. The influence of cavity parameters (inclined angle, cavity length and diameter, cavity number) on the mechanical properties and AE behavior of coal specimens were investigated by biaxial compression tests. Besides, the stress distribution and permeability evolution around the cavity were studied using FLAC3D combined with COMSOL software. Finally, the field tests were conducted in LiCun Coal Mine. The results indicate that a significant reduction in the compressive strength of coal specimens with increasing cavity dimensions. Notably, the peak stress in coal specimens decreased significantly as the cavity length, diameter, and number increased, by up to 42.09%, 39.38%, and 57.83%, respectively. In contrast, the peak stress increased with the cavity inclination angle, and it was about 1.14 times higher for specimens with a 90° angle than for those with a 15° angle. It is also found that the cavity inclination reduces the damage and acoustic emission activity of the specimen, while the cavity volume increases them and weakens the rock-bearing capacity. The failure modes of all specimens are shear failure combined with surface spalling. Numerical simulations employing FLAC3D and COMSOL software corroborated these results, demonstrating enhanced pressure relief and increased permeability around the cavities. Field tests conducted in the LiCun Coal Mine provided practical evidence of the method's efficacy, with a more than 3-fold increase in gas drainage concentration and volume observed compared to traditional drilling methods. By adopting mechanically over-excavated cavities, not only is the efficiency of gas drainage significantly improved, but also the safety and productivity of mining operations are enhanced. This study offers a promising and impactful solution for addressing gas drainage challenges in soft coal seams.

Efficient and robust CO2 hydrogenation to methanol achieved by copper nanoparticles anchored in copper phyllosilicate core-shell nanoreactor

Methanol synthesis by CO2 hydrogenation is a key process in a sustainable methanol-based economy. Copper silicate (CuSiO3) is considered as efficient for hydrogenation of C-O/CO bonds due to the synergistic effect from its unique dual-sites of Cu0-Cu+. However, it still confronts great obstacles of poor CO2 conversion and low methanol selectivity. Herein, we designed a core-shell CuSiO3 nanoreactor by hydrothermal method, the cavity of which between core and shell provided the reaction space for CO2 and H2 in CO2 hydrogenation. Interestingly, the cavity of the nanoreactor could be tuned by the hydrothermal time, and the product selectivity altered accordingly. Intrinsically, because of the spatial restriction effect of reactants, the reactant especially hydrogen can be enriched on the concave surface of nanotubes and hollow spheres, leading to a favorable activity. Furthermore, the longer diffusion path derived from the increased cavity volume would cause a deep hydrogenation to CH4. Based on this, we chose the nanoreactor with suitable cavity volume to impregnate copper nanoparticles to increased the active sites and regulate the ratio of Cu0/Cu+, achieving remarkable catalytic activity (the conversion of CO2 is 19.7% and yield of methanol reaches up to ∼18%). Moreover, the copper nanoparticles could be anchored by the core and shells, contributed to an excellent stability of the catalytic system (>120 h).

Structure and scaling of the middle ear in domestic dog breeds.

Although domestic dogs vary considerably in both body size and skull morphology, behavioural audiograms have previously been found to be similar in breeds as distinct as a Chihuahua and a St Bernard. In this study, we created micro-CT reconstructions of the middle ears and bony labyrinths from the skulls of 17 dog breeds, including both Chihuahua and St Bernard, plus a mongrel and a wolf. From these reconstructions, we measured middle ear cavity and ossicular volumes, eardrum and stapes footplate areas and bony labyrinth volumes. All of these ear structures scaled with skull size with negative allometry and generally correlated better with condylobasal length than with maximum or interaural skull widths. Larger dogs have larger ear structures in absolute terms: the volume of the St Bernard's middle ear cavity was 14 times that of the Chihuahua. The middle and inner ears are otherwise very similar in morphology, the ossicular structure being particularly well-conserved across breeds. The expectation that larger ear structures in larger dogs would translate into hearing ranges shifted towards lower frequencies is not consistent with the existing audiogram data. Assuming that the audiograms accurately reflect the hearing of the breeds in question, oversimplifications in existing models of middle ear function or limitations imposed by other parts of the auditory system may be responsible for this paradox.

Experience in managing patients with X-linked congenital retinoschisis

AIM: To describe the clinical manifestations and management experience of patients with X-linked congenital retinoschisis (XLRS).&#x0D; MATERIAL AND METHODS: The study was conducted in the ophthalmology department of the multidisciplinary clinical medical center Bonum (Yekaterinburg). Two brothers with XLRS were under observation. They underwent complete ophthalmological examinations, including electrophysiological examinations, optical coherence tomography (OCT), and fundus photoregistration. The mother refused genetic testing.&#x0D; RESULTS: Both siblings had early (up to 1 year) manifestations of central foveolamellar and peripheral bullous retinoschisis. The parents are phenotypically healthy, and the relatives have no hereditary eye diseases. The younger brother had a progressive peripheral retinoschisis and underwent barrier laser retinopexy; as a result, the progression stopped at the last examination. Acetazolamide 125 mg given orally daily for 4 weeks did not have a noticeable effect on the volume of bullous cavities. The older brother had been under observation for 4 years, and spontaneous closure of retinal cavities on the periphery in one eye and retinal detachment in the other after surgical treatment of retinoschisis were observed.&#x0D; CONCLUSION: Clinical cases of long-term follow-up of two brothers with XLRS are described. OCT is indicated to diagnose, assess the length and the state of the vitreoretinal interface, and monitor XLRS. Electroretignography is a specific and sensitive method for the complex diagnosis of XLRS. Barrier laser retinopexy is indicated for progressive peripheral retinoschisis. The efficacy and safety of carbonic anhydrase inhibitors in patients with XLRS require further study.

Cellular automata simulation of cavity growth during creep of Al–Mg alloy

Lifespan of high temperature services could seriously be affected by cavitation and thus, prediction of this phenomenon is considered as a significant task. A two-dimensional cellular automata approach coupled with governing equations for cavity nucleation and growth was developed to predict the size and distribution of cavities. Different growth mechanisms including diffusion and strain-controlled processes were taken into account and also, the coalescence phenomenon and the corresponding growth rate were considered in the model. The creep experiments were conducted on AA5052 under different temperatures and applied stresses such as 15 MPa at 300 °C, 20 MPa at 300 °C and 30 MPa at 270 °C for providing essential data points. Afterwards, the optical metallography and the scanning electron microscopy were performed to characterize the cavity size and distribution. The obtained results were then used to determine material constants and validate the simulation outcomes and a reasonable consistency was found between the predictions and experimental data. It was found that the strain-controlled growth is the dominant mechanism for strains larger than 0.04 while the coalescence of cavities might be significant when cavity volume fraction is higher than 0.5%. The simulations showed that the large cavity radius was observed when growth rate due to coalescence was implemented in the model.

The changes in abdominal wall muscles following incisional hernia wall reconstruction.

The objective of incisional hernia surgery is to achieve the restoration of abdominal wall anatomical and physiological functions. This study aims to investigate the impact of abdominal wall reconstruction on abdominal muscle alterations by measuring the preoperative and postoperative changes in abdominal wall muscles in patients undergoing incisional hernia repair. For patients undergoing open incisional hernia abdominal wall reconstruction, preoperative and postoperative abdominal CT scans were analyzed at a minimum of 3months post-surgery. 3D Slicer software was utilized for measuring preoperative and postoperative changes in abdominal cavity volume, abdominal muscle volume, as well as muscle volume, cross-sectional area, and abdominal circumference at specific levels. The acquired data were subjected to statistical analysis using SPSS software. A total of 40 patients meeting the inclusion criteria underwent open incisional hernia repair surgery. Some of these patients required component separation technique (CST) due to the larger size of the hernia sac. The abdominal muscles surrounding the hernia ring were defined as the "damaged group," while the remaining abdominal muscles were defined as the "undamaged group." Measurements revealed a significant increase in the volume of rectus abdominis, external oblique, internal oblique, and transversus abdominis muscles in the damaged group. Similarly, there was a corresponding increase in the volume of rectus abdominis, external oblique, internal oblique, and transversus abdominis muscles in the undamaged group. After abdominal wall reconstruction in incisional hernia patients, not only is their anatomical structure restored, but the overall biomechanical integrity of the abdominal wall is also repaired. The damaged muscles are subjected to renewed loading, leading to the reversal of disuse atrophy and an increase in muscle volume.

Effects of melatonin against experimentally induced apical periodontitis in rats.

Apical periodontitis is an inflammatory condition resulting from microbial invasion in the root canal system, causing periapical tissue destruction and bone resorption. This study investigated melatonin's effects, known for its antioxidant and anti-inflammatory properties, on experimentally induced apical periodontitis in rats. Three groups of rats were studied: control, apical periodontitis and apical periodontitis with melatonin treatment. Proinflammatory cytokines and enzyme levels in blood serum were measured, and micro-CT analysis assessed bone resorption. Results showed significantly elevated cytokines and enzyme levels in the apical periodontitis group compared to the control. However, in the melatonin-treated group, these levels were significantly reduced (p < 0.01-0.001). Micro-CT analysis indicated decreased periapical resorption cavity volume and surface area with melatonin treatment. This suggests that systemic melatonin administration can mitigate inflammation and reduce bone resorption in experimentally induced apical periodontitis in rats, potentially holding promise for human endodontic disease treatment pending further research.

Botulinum Toxin and Progressive Pneumoperitoneum in Loss of Domain Ventral Hernias: A Systematic Review.

Introduction: Preoperative progressive pneumoperitoneum (PPP) and botulinum toxin A (BTX) have been used together in the preoperative preparation of patients with loss of domain hernias. This study aims to evaluate the efficacy and safety of the combined use of PPP and BTX. Methods: A systematic electronic search was performed according to the PRISMA criteria. A literature search of scientific articles was conducted up to December 2023. Articles were chosen based on the reference to BTX and PPP in loss of domain ventral hernias with a defect width greater than 10cm before surgery. The GRADE methodology and the modified Newcastle-Ottawa scale were used to assess the quality of the studies. Results: The research yielded seven articles, with 217 patients analysed in total. BTX was performed 29.5 ± 1.7 days before surgery and PPP was inflated 14.8 ± 5.8 days before surgery. PPP complications were reported in 25.6% of patients, The average reduction of the volume of hernia (VH)/volume of the abdominal cavity (VAC) ratio was 7.6% (range 0.9%-15%). Only 40 patients (18.4%) required a PCS or TAR to repair the loss of domain hernias. The SSI and SSO rates were 17.5% and 26.2%, respectively. No differences in SSI and SSO rates were found between the different repair techniques. The recurrence rate was 5.9% (13/217). Recurrence was significantly higher in patients who underwent IPOM repair than other techniques (p < 0.001). Conclusion: BTX and PPP may be useful tools for the management of loss of domain hernias presenting lower SSI and SSO. The combination of BTX and PPP reduces the use of more invasive repair techniques.

A multifunctional metastructure with energy dissipation and low-frequency sound-absorption optimized for decoupling by genetic algorithm

A multifunctional metastructure has been proposed with the aim of having both energy-absorbing and sound-absorbing capabilities through the use of a rubber-filled re-entrant honeycomb frame. The acoustic and mechanical properties of the metastructure are decoupled utilizing a genetic algorithm so that the properties can be designed separately. The re-entrant honeycomb frame has the role of energy absorption, while the rubber filling allows the structure to form a Helmholtz-type absorbing material. The form of deformation of the structure under quasi-static compression is investigated by means of experiments and simulations, which are used to determine the variation of the cavity volume with compression. With the optimization by genetic algorithm, the first-order and second-order acoustic structures with excellent acoustic performance before and after compression have been obtained. At the same time, a continuous broadband sound- and energy-absorbing metastructure has been produced by combining these two structures. This work provides a remarkably new strategy for the integrated design of sound- and energy-absorbing structures and has a significant prospect for engineering applications such as aerospace engineering.

A Conjugated Phenylene Nanocage with a Guest-Adaptive Deformable Cavity.

The highly strained, phenylene-derived organic cages are typically regarded as very rigid entities, yet their deformation potential and supramolecular properties remain underexplored. Herein, we report a pliable conjugated phenylene nanocage by synergistically merging rigid and flexible building blocks. The anisotropic cage molecule contains branched phenylene chains capped by a calix[6]arene moiety, the delicate conformational changes of which endow the cage with a remarkably deformable cavity. When complexing with fullerene guests, the cage showcases excellent guest-adaptivity, with its cavity volume capable of swelling by as much as 85 %.

A Conjugated Phenylene Nanocage with a Guest‐Adaptive Deformable Cavity

AbstractThe highly strained, phenylene‐derived organic cages are typically regarded as very rigid entities, yet their deformation potential and supramolecular properties remain underexplored. Herein, we report a pliable conjugated phenylene nanocage by synergistically merging rigid and flexible building blocks. The anisotropic cage molecule contains branched phenylene chains capped by a calix[6]arene moiety, the delicate conformational changes of which endow the cage with a remarkably deformable cavity. When complexing with fullerene guests, the cage showcases excellent guest‐adaptivity, with its cavity volume capable of swelling by as much as 85 %.

Use of Botulinum Toxin and Pneumoperitoneum for Hernias with Loss of Dominance

When the abdominal cavity's material migrates to the hernial sac (HSV) and the HSV/abdominal cavity volume ratio exceeds 25%, systemic alterations known as "loss of domain" occur, resulting in an estimated 5–30% of cases of post-incisional ventral hernia. Usage of botulinum toxin appears to be a secure way to do a tension-free repair on treatment for hernias with loss of dominance.

Acidity-controlled hollow HZSM-5 for lignite pyrolysis volatiles valorization to light aromatics

The hollow HZSM-5 (HZ5) was evaluated for catalyzing reforming of lignite volatiles into light aromatics (LAs), with special emphasis on the effect of catalyst acidity. Hierarchical HZ5 variants with diverse cavity volumes and mesopores in the shell were synthesized using varying concentrations of TPAOH and TPABr. The results revealed that the desilication-recrystallization induced a reconfiguration of catalyst acidity by TPA+ and OH–, leading to increased Brønsted acid sites (BAS) and accessibility to outer surface acids. The resulting hollow zeolites, featuring elevated BAS, notably enhanced LAs yield, particularly benzene among monocyclic aromatic hydrocarbons, while decreasing oxygenates in the liquid product. Notably, correlation coefficients between LAs yields and catalyst physical properties underscored the dominance of catalyst acidity, especially BAS, as the key driver for increased LAs formation compared to mesoporous volume.

Morphological study of pulp cavity anatomy of canine teeth in domestic cats using micro-computed tomography.

An understanding of the pulp cavity anatomy of individual teeth is essential for success during endodontic therapy. The objective of this study was to document pulp cavity anatomy and summarize numerical data of maxillary and mandibular canine teeth of domestic cats using micro-computed tomography (micro-CT). Thirty-nine canine teeth from eleven domestic cat cadaveric specimens were extracted and prepared for scanning. Segmentation of the pulp cavity was performed using the Avizo (v2022.2) software package. The morphological features of the pulp cavity including overall shape, configuration, presence of apical deltas and lateral canals was recorded. A quantitative analysis was performed on thirty-one teeth to explore associations between pulp cavity volume and length, apical delta length, maximum apical delta foramina number and cusp-to-tip length using a linear mixed model. Correlation between pertinent continuous variables was assessed using a Pearson's correlation test. Most pulp cavities exhibited varying curvature and ranged from a cylindrical configuration in the coronal third to an ovoid configuration in the middle to apical third. A ribbon-like flattened canal was observed in 6/31 teeth (19%). All canine teeth depicted an apical delta with various configurations except for two teeth that showed a single canal exiting at the apex. In 15/31 teeth (48%), the primary root canal within the apical delta could be clearly identified and in 16/31 (52%) the primary root canal was indiscernible. The results showed that the pulp cavities of maxillary canine teeth were significantly larger and longer and the cusp-to-tip length was longer, when compared to mandibular teeth. The apical delta length was negatively correlated to the volume of the pulp cavity. No specimens depicted lateral canals. This study revealed that the anatomy of the canine tooth pulp cavity in cats can vary considerably and should be a consideration when performing thorough debridement, shaping and obturation of the endodontic system.

Medium-term effects of rapid maxillary expansion on nasal cavity and pharyngeal airway volumes considering age as a factor: A retrospective study

ObjectivesThe medium-term effects of rapid maxillary expansion (RME) on nasal cavity (NC) and upper airway (UA) dimensions based on chronological age are still unclear. This retrospective study evaluated the medium-term changes occurring in the NC and pharyngeal airways (PA) after RME in two distinct age-based cohorts of patients. MethodsThis retrospective study included 48 subjects who underwent RME grouped in two cohorts: a 6–9-year-old group (EEG group: early expansion group - 25 subjects) and an 11–14-year-old group (LEG group: late expansion group - 23 subjects). NC and PA volumes were analyzed from CBCT imaging segmentation before RME (T0) and twelve months after RME (T1). The amount of maxillary expansion (PW) and minimal cross-sectional area (CSmin) were also considered. ResultsAll PAs’ volumetric sub-regions, CSmin and PW showed a significant volumetric increment (p < 0.05). Inter-group comparisons showed significant differences (p < 0.05) for nasopharynx and CSmin parameters (p < 0.05), while no significant changes were recorded for the other UA's sub-regions and PW (p > 0.05). According to a deviation analysis, part of the UA increase (more marked for the nasopharynx area) may have occurred due to reduced adenotonsillar tissues, which were larger in the EEG group. ConclusionsTwelve months after treatment, clinicians should not expect changes in the UAs dimensions to be solely related to treatment effects of RME; instead, normal craniofacial growth changes and spontaneous regression of the adenotonsillar tissue could represent the most significant factors influencing UAs changes. Clinical SignificanceFrom the clinical perspective, the results of the present study encourage caution when considering the therapeutic effects of RME on airways dimensions.

Does Miniscrew-Assisted Rapid Palatal Expansion Influence Upper Airway in Adult Patients? A Scoping Review.

(1) Objective: This scoping review evaluates the effects of miniscrew-assisted rapid palatal expansion (MARPE) on different regions of the upper airway in adult patients and investigates various methods of measurement. (2) Methods: The search encompassed Pubmed, Cochrane Library, Scopus and Web of Science. This review was conducted following the PRISMA_ScR guidelines, and the inclusion criteria for examined studies were chosen in accordance with the PICOS framework. (3) Results: Seven studies were included in this review, comprising four retrospective studies, one prospective and two case reports. All studies involved the use of Cone Beam Computed Tomography (CBCT) for measurements of the areas of interest. The percentage of increase in the volume of the nasal cavity varied between 31% and 9.9%, depending on the study. Volumetric variations in the nasopharynx were reported as increases between T0 (before expansion) and T1 (immediately after expansion) of 6.4%, 20.7% and 14.1%. All studies considered T0 before expansion and T1 immediately after expansion. Only one study evaluated remote follow-up to assess if the results were maintained after one year. (4) Conclusions: MARPE appears to lead to a statistically significant increase in the upper airway, especially in the nasal cavity and nasopharynx immediately after expansion. However, further prospective and retrospective trails with long-term controls are required to verify the effects of MARPE on the upper airway.

Subjective and objective comparative analysis of nasal ventilation function before and after nasal septoplasty

Objective:To investigate the changes of nasal ventilation before and after septoplasty by using NOSE scoring scale and nasal function examination, and to explore the correlation between subjective nasal obstruction and nasal function examination and its clinical application value. Methods:A total of 129 cases of nasal septum deviation from December 2021 to April 2023 in our hospital were selected for study. All patients underwent septoplasty. Nasal obstruction symptom evaluation（NOSE） was performed in all patients before surgery and 3 months after surgery. nasal minimal cross-sectional area（MCA） and nasal cavity volume（NCV） were recorded by nasal acoustic reflex, nasal resistance meter and nasal respiration apparatus, nasal resistance（NR）, distance between the nostril to minimum cross-sectional area,（the distance between the nostril to minimum cross-sectional area, MD）, nasal inspiratory volume（IV）, nasal expiratory volume（EV）, the nasal partitioning ratio, NPR includes objective indicators such as inspiratory volume difference ratio（NPRi） and expiratory volume difference ratio（NPRe）. Paired test was used to compare and analyze the changes of various indicators before and after surgery, and the difference（P<0.05） was statistically significant, and Pearson correlation linear analysis was used to analyze the correlation between subjective and objective indicators. Results:There were statistically significant differences in NOSE score, NCV, NR, MD, EV, IV, NPRe and NPRi of 129 patients before and after surgery（P<0.05）, while there was no statistically significant difference between MCA before and after surgery（P>0.05）. Preoperative NOSE score was correlated with NR, NCV, EV, IV, NPRe and NPRi（P<0.05）, but not with MD and MCA（P>0.05）. There was correlation between NOSE score and NR, MCA, NCV, EV, IV, NPRe and NPRi（P<0.05）, but no correlation between nose score and MD（P>0.05）. Conclusion:The subjective NOSE scale combined with nasal function test has certain clinical reference value in evaluating the surgical effect of patients with deviated nasal septum.