Clean Cavity Research Articles

Numerical Study on the Unusual Vibration Load Characteristics and Mechanisms of the Front Landing Gear Compartment

Civilian aircraft can experience noticeable vibrations in the cockpit and cabin due to mechanical faults during flight. To address this issue, a hybrid approach was utilized to investigate fluid-induced vibration load characteristics in the front landing gear compartment under different hatch opening angles. The results reveal that the root mean square (RMS) of cumulative pressure loads on both small and large hatches under different opening angles is largest at a 15°. For all the simulated cases (0°, 5°, 10°, 15°, 20°), the power spectral density (PSD) results of the chosen monitoring points on the inner wall of the large hatch exhibit broadband frequency characteristics, and the peak PSD values for the chosen monitoring points on the outer wall of the small hatch exhibit a significant concentration of energy at approximately 75 Hz. The peak PSD values for the selected monitoring points on the inner wall of the small hatch demonstrate a more uniform distribution of energy. Utilizing the iso-surface of Q-criterion, spatial streamlines, and streamlines at different cross-sections to analyze flow characteristics, the study investigates the fluctuating load mechanisms of the compartments. The results indicate that unsteady loads stem from the blunt edges of the hatches, which induce unsteady flow and spanwise flow. Geometric gaps between different locations cause flow separation, and the flows inside the compartment exhibit characteristics similar to those of a clean cavity. Furthermore, the mutual interference can be described using circulating flow and spanwise flow, resulting in flow unsteadiness. The flow separation zones enlarge and vortex intensity increases with the increase of the hatch opening angle from 0° to 15°; then, their values decrease as the hatch opening angle increases from 15° to 20°. These variations explain the maximum RMS of cumulative pressure loads at 15°.

TRANSFUSION AND INFUSION THERAPY FOR MASSIVE BLOOD LOSS. PART 1, UNEXPECTED INTRAOPERATIVE HAEMORRHAGE

TRANSFUSION AND INFUSION THERAPY FOR MASSIVE BLOOD LOSS. PART 1, UNEXPECTED INTRAOPERATIVE HAEMORRHAGE

Antibacterial Effectiveness Test of Potato Peel Ethanol Extract (Solanum tuberosum L.) against Lactobacillus acidophilus: An In Vitro Study

Lactobacillus acidophilus is one of the bacteria that play a major role in the caries process. It is recommended to use cavity cleanser to clean and disinfect caries cavities post-preparation. However, the currently used cavity cleansers, 2% chlorhexidine digluconate and sodium hypochlorite, have limitations. Thus, exploring natural alternatives, like potato peel, as a cavity cleanser material is necessary. This study aims to determine the antibacterial effectiveness of the ethanol extract of potato peel (S. tuberosum L.) on the growth of L. acidophilus. The method used was true experimental laboratories with a post-test-only control group design and broth dilution. The samples were divided into 8 groups, including 6 treatment groups with varying concentrations of extract (100%; 50%; 25%; 12.5%; 6.25%; and 3.125%), positive control, and negative control. Each group was repeated 4 times. The Minimum Inhibitory Concentration (MIC) was determined by observing solution turbidity in the tubes which began to appear clear after 24 hours of incubation, while the Minimum Bactericidal Concentration (MBC) was determined by the absence of bacteria that grew on media after being given the test solution and incubated for 24 hours. The MIC of potato peel ethanol extract on the growth of L. acidophilus could not be determined, while the MBC was at a concentration of 50%. The Kruskal-Wallis test showed that concentration levels had a significant difference in the average number of L. acidophilus colonies. The ethanol extract of potato peel (S. tuberosum L.) has antibacterial effectiveness against the growth of L. acidophilus.

Dentifrice- Fricare your Teeth

Oral hygiene maintenance is the part and parcel of the overall oral health. The entire treatment phases and maintenance phases rely on the extent of clean oral cavity. We have with chemical and mechanical plaque control measures for maintenance. Dentifrices come handy in our mechanical control for use along with toothbrushes. Dentifrices come in wide ranges with additional therapeutic ingredients added to them. Toothpastes are often used in treatment of halitosis and gingivitis as a delivery system for therapeutic agents such as antimicrobials and ant sensitivity agents

Oral health practices among 10-15 years of government school children in Chengalpattu district, India: a cross-sectional survey

Background: Oral health is a fundamental part of the general health and well-being of an individual. Oral hygiene refers to the practice of maintaining a clean oral cavity to prevent dental problems like dental cavities, bad breath, gingivitis, and periodontitis. Aim was to assess oral health practices among 10-15 years of government school children in Chengalpattu district, India.Methods: This cross-sectional study included 1500 government school children aged 10-15 years based on the guidelines of the strengthening the reporting of observational studies in epidemiology. Each child was asked about the dental hygiene practices.Results: The study population was composed of 545 (36.3%) participants who belonged to the 10-12-year-old category and 955 (63.7%) belonged to the 13-15 years category. While assessing the oral hygiene practices of the children, 86.1% of children used toothbrush and toothpaste as oral hygiene aids. In our study more than half of the students 59% reported that they brush only in the morning that 32.8% of children felt stinky sometimes in their oral cavity. Only around 28.5% had used the service of a dentist during the last 6 months and about 12.8% in the last 1 year.Conclusions: The study results concluded that oral hygiene practices were enhanced among male children when compared to female children and showed a positive attitude in preserving appropriate oral health.

Flow Characteristic Study of High-speed Cavity Based on Detached-eddy Simulations

The cavity is widely used in the advanced flight vehicle. However, there are also some new aerodynamic characteristic when cavity is exposed in high-speed flow. The flow characteristic of high-speed cavity is studied in this paper based on detached-eddy simulation method. The M219 cavity benchmark under transonic flow is used as the validation case for numerical methods and grid strategy. Comparison of predicted sound pressure levels and spectra against the wind tunnel experiment has proved that the numerical methods capture the major oscillation dynamics inside the cavity. The aerodynamic characteristic of cavity with a store is investigated in this paper, there are three vortexes in the cavity and the main vortex in the middle rotates around the store. The shear layer breaks earlier compared with clean cavity due to the turbulent flow around the store. However, the small store has little influence to the sound pressure level of cavity.

Manual Vacuum Aspiration in IUFD 18 Weeks

Manual Vacuum Aspiration (MVA) is an action to evacuate the uterine cavity up to 14 weeks gestation. In a more extensive pregnancy, it is worried that the action of the MVA is less clean so that it will still repeat the action of sharp curettage. This article reports a multigravida aged 42 years old, G5P2A2, intrauterine fetal death (IUFD) at 18 weeks, undergoing MVA. Diagnosis of IUFD was performed using ultrasound examination. Before MVA was done, the patient was previously given 100 μg of misoprostol orally for dilation. This pregnancy was the third pregnancy with a second husband, all of whom had abortions. Manual Vacuum Aspiration had a minimal risk of uterine injury. After MVA was conducted, ultrasound examination was repeated to confirm a clean uterine cavity. It had been carried out on an indication of IUFD of 18 weeks gestation with the result of a clean uterine cavity and minimal bleeding. Furthermore, Post-Abortion Intra-Uterine Device (PAIUD) was installed adequately, not causing complaints. Based on the result, it can be concluded that MVA is effective for evacuation of uterine cavities on 18 weeks gestation.

A comparative study on nitridation mechanism and microstructural development of porous reaction bonded silicon nitride in the presence of CaO, MgO and Al2O3

ABSTRACT During the in-situ nitridation of Si in the presence of CaO, MgO and Al2O3 formation of reaction bonded silicon nitride ceramics (RBSN) having various microstructures indicated the possibility of different nitridation mechanisms operating. Experimental evidence suggested that, whereas the morphology of pores was controlled by nitridation of Si(g) in CaO-RBSN and SiO(g) in Al2O3-RBSN, a combination of these two reactions occurred during the nitridation of the MgO-RBSN. By inhibiting the growth of whiskers and maximizing the α/β ratio, the CaO addition led to the formation of matte grains creating clean spherical cavities with d < 40 µm and flexural strength of 0.8 MPa. In contrast, when using Al2O3 additions, a microstructure with a very low α/β ratio, fine inter-particle pores and 2.4 MPa flexural strength, reinforced with interlocking whiskers, was produced. The highest porosity (85%) and the lowest strength (0.3 MPa) occurred in the MgO-RBSN, which was composed of both matte grains and fine whiskers. Local supersaturation and low content of β-nuclei led to the formation of anisotropic β-grains with a bimodal microstructure in heat-treated CaO-RBSN while a unimodal microstructure was observed in heat-treated MgO-RBSN. No porosity loss or β-grain growth occurred in the heat-treated Al2O3-RBSN.

Control effect on deep cavity noise by slanted walls at low Mach numbers

Experimental and numerical studies on noise radiated by flow past a rectangular two-dimensional deep cavity with passive control are conducted to research the mechanism of cavity noise reduction at low Mach numbers. The clean cavity has a depth-to-length ratio of 1.5 and a width-to-length ratio of 3. The passive control method is used by slanting the front and rear walls. Using acoustic microphones, both the surface noise and far-field noise are tested in an aeroacoustic wind tunnel. It is observed that the slanted rear wall can suppress the noise effectively, but for the slanted front wall, the tones will be enhanced at some velocities. Numerical simulation is conducted to reveal the mechanism. The results reveal that the slanted rear wall can reflect the unsteadiness back to the shear layer and break up the vortices in it. These vortexes will diffuse after impacting the rear wall and prevent the perturbation from moving deeper, which brings a stable flow field into the cavity. As for the slanted front wall, the vortices will be enlarged and become accelerated in the shear layer, which makes the impingement of it to the rear wall more intense, thus leading to an increase in the noise level.

Digestive Manifestation in COVID-19 Patient Complicated by Occlusive Syndrome Admitted to Intensive Care in a Case

We report the case of a 39-year-old patient with a history of chronic gastritis, functional colopathy and appendectomy, referred by another public institution for severe abdominal pain. He had been admitted 6 days previously for nausea, vomiting, diarrhea, fever, asthenia since the onset of dyspnea with 89% desaturation in ambient air and a dry cough. A diagnosis of gastroenteritis was made and treated without success. The appearance of abdominal distension and bloating motivated his transfer to the CTPI where the rRT-PCR was carried out positive and an X-ray of the abdomen without preparation which had demonstrated a significant aerocoly with agglutination of handle. Surgical management under general anesthesia found a clean cavity after coeliotomy, multiple intestino-intestinal, intestino-parietal and omentum-parietal adhesions. The gesture consisted of an adhesiolysis, omentectomy. The postoperative follow-up was favorable with resumption of transit on D5 postoperative. Put under the COVID-19 treatment protocol, the rRT-PCR was negative on D13, output on D14 and removal of the D19 files without postoperative complications.

Aeroacoustic Investigation of Passive and Active Control on Cavity Flowfields Using Delayed Detached Eddy Simulation

In the present study, CFD simulation with delayed detached eddy simulation (DDES) is performed to investigate an open cavity at Mach 0.85. A clean cavity and cavity with passive and active control methods, including sawtooth spoiler, flat-top spoiler, crossflow rod, and steady leading edge blowing, are analyzed. The results obtained from all the control methods are compared with clean cavity, and all the flow control methods show positive effect on the overall sound pressure level reduction with the decrement up to 8 dB. The effect of active control on sound pressure level in the cavity is much better than that of passive control, with the magnitude of tone noise decreasing by 20-30 dB. The main focus of this investigation is to test the noise suppression effect by passive and active control methods.

Field-Enhanced Superconductivity in High-Frequency Niobium Accelerating Cavities.

The discovery of nitrogen-doping treatment revealed that the radio frequency surface resistance of niobium resonators may be significantly reduced when nitrogen impurities are dissolved as interstitials in the material. A peculiar behavior exhibited by N-doped cavities is the anti-Q slope, i.e., a reduction in the temperature-dependent component of the surface resistance as a function of the accelerating field. This unusual trend in the surface resistance behavior has been attributed to the presence of interstitial nitrogen in the niobium lattice after the doping treatment. This Letter presents a focused study on the field dependence of the temperature-dependent component of the surface resistance as a function of the cavity resonant frequency. The findings show that the anti-Q slope may appear even in clean niobium cavities if the resonant frequency is high enough, which suggests new routes toward understanding the anti-Q slope effect.

Abstract 2152: Optimizing therapies for drug-resistant ovarian cancer stem cells using aCAM-PDX model

Abstract Purpose: To develop rapidly operational CAM-PDX (chorioallantoic membrane-patient derived xenograft) tumor models that morphologically resemble human tumors in order to perform therapeutic/efficacy studies targeting TWIST, a transcription factor expressed in cancer stem cells critical to embryonic development, and aberrantly activated in many cancers. This CAM-PDX model was used to optimize mesoporous silica nanoparticle with hyaluronic acid (MSN-HA) and siTWIST in combination with cisplatin, as well as screen other drug therapies (e.g., doxorubicin) that will benefit ovarian cancer patients. Experimental Procedures: Fertilized eggs were obtained from AA Lab Eggs, Inc. The eggs were incubated for 10 days at 100°F and 60% humidity. At day 10, a small window was opened on the surface of the egg and the CAM was dropped. A teflon ring was inserted, 50µg/µL of cancer cells (1 million cells) were deposited, and the window was covered with transparent film dressing and replaced in the incubator. 120µL of siTWIST (with MSN-HA) and/or 100µL of cisplatin were administered intravenously (day 13 and 14, respectively). On day 17, the eggs were imaged using Leica microscope. The CAM-PDX models were developed first with standard EOC cell lines and second using primary cells from patient tissues transfected with eGFP/ffluc for imaging growth, histology, and tumor biodistribution studies. Toxicity studies were performed by administering doxorubicin at varying doses and with different nanoparticle delivery methods. Results: The study showed that we were able to grow patient-derived tumors in the egg CAM model. Moreove,r a histologic comparison of CAM tumors and ovarian patient tumors reveals highly similar morphology. Furthermore, when treated with chemotherapy, the tumor regressed, as it does in patients. Our toxicity study demonstrates that surrounding organs, as well as the embryo, were spared from detrimental off-target effects of doxorubicin when the drug was delivered inside nanoparticles, as opposed to free-drug, as demonstrated by final egg survivability count. Images show free-drug administration of doxorubicin damaged organs in the peritoneal cavity while nanoparticle administration of doxorubicin resulted in a clean cavity and sound organs. Our study also shows that our siTWIST MSN-HA sensitized drug-resistant cancer stem cells to cisplatin. Finally, our results also show that the optimal treatment for tumor dissemination in the PDX-CAM system is the combination of siTWIST MSN-HA and cisplatin compared to cisplatin alone. Conclusions: This study provides a much-needed, cost-effective means to grow PDX lines from patient tissues. The CAM-PDX system provides a faster means of collecting information on the efficacy of novel MSNs for the delivery of siRNA and drugs than expensive mouse models. Thus, the CAM-PDX model is beneficial toward moving us closer to translation and application in other cancers. Citation Format: Altagracia Contreras, Sophia Allaf Shahin, Laura E. Ratliff, Shirleen I. Simargi, Ruining Wang, Binh Vu, Thanh H. Dellinger, Jeffrey I. Zink, Fuyuhiko Tamanoi, Julia Unternaehrer-Hamm, Carlotta A. Glackin. Optimizing therapies for drug-resistant ovarian cancer stem cells using aCAM-PDX model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2152.

EDUCATION ON DISASTER PREPAREDNESS AND RESPONSE OF DENTAL HYGIENISTS IN VOCATIONAL UNIVERSITIES/COLLEGES IN JAPAN

Due to the increasing global frequency of disasters, disaster preparedness training is becoming more important. The fact that Japan has many earthquakes is well known worldwide. In the field of nursing, the importance of disaster preparedness education in universities has gradually increased in Japan. Many people lose their homes in earthquakes and have to live in shelters. The relationship between pneumonia and the oral cavity environment is understood; for example, in certain shelter environments that provide an insufficient water supply, oral cavity hygiene is affected. Keeping a clean oral cavity prevents death from pneumonia, especially in elderly people. To keep a clean oral cavity, the role of dental hygienists is important. In Japan, education on disaster preparedness and response for dental hygienists in vocational university/college is rarely provided. Therefore, this is the focus of our research. We administered an anonymous questionnaire survey to 119 dental hygienist training schools by mailing them surveys asking about their education on disaster preparedness and response for dental hygienists. In this paper, we report on the education on disaster preparedness and response for dental hygienists in vocational universities and colleges in Japan.

Experiment and analytical model of laser milling process in soluble oil

The liquid-assisted laser machining process is a promising method to cut materials with minimum thermal damage caused by laser, and water is typically used in the process due to its high thermal conductivity, nontoxicity, and relatively low price. However, water can intrinsically oxidize ferrous metals and in turn deteriorate the workpiece through corrosion during laser ablation in water. This study has for the first time proposed laser ablation in soluble oil to effectively cut the ferrous metals by using laser in a high cooling rate and low potentiality of corrosion to the metals. A nanosecond pulse laser was used to scan over the AISI H13 steel sheet to create a square cavity, while the workpiece surface was covered by a thin and flowing soluble oil film throughout the laser milling process. The effects of laser scan overlap, traverse speed, and liquid flow rate on cavity dimensions and milled surface morphology were experimentally examined. The results revealed that a clean and uniform cavity with a smooth machined surface can be attained by using 70% scan overlap, 6 mm/s traverse speed, and 3.9 cm3/s soluble oil flow rate. Furthermore, analytical models based on heat transfer equations were formulated to predict the cavity profile and cooling of molten droplets in flowing liquid. The predicted profile was found to correspond well to the experiment, and the calculated temperature of cut particles can endorse the experimental findings on debris deposition and recast formation. The implications of this study could bring a new technological approach for damage-free fabrication and fine-scale manufacturing.

The application of baby hand and mouth wet wipes to the nursing of patients with oral care

Objective To explore a new comfortable, effective and safe oral-nursing method, which is not only more acceptable for fully conscious patients but also more practical and convenient for nurses without increasing labor intensity or time. Methods A total of 207 conscious inpatients with indwelling gastric tube who could not take care of themselves were enrolled in this study and randomly divided into treatment group (101 cases) and control group (106 cases). The control group was treated with 0.9% saline-soaked cotton ball to conduct oral nursing, while the treatment group were treated with the baby hand and mouth wet wipes instead.The oral cleanliness degree (nurses' evaluation), comfort level (patients' evaluation), nursing time, bacterial constitution of oral secretion and incidence rate of complication were assessed 7 days after oral-nursing. Results The oral cleanliness degree and comfort level of the treatment group were obviously higher than that of the control group (P<0.05). The nursing time and the incidence rate of complication were significantly lower than that of the treatment group (P<0.05). Conclusion The baby hand and mouth wet wipes instead of the saline-soaked cotton ball to conduct oral nursing can clean oral cavity comprehensively and improve the breathing odor, reduce the oral complications, reduce the nurses' work labor and is more acceptabl for patients as well.This modified oral-nursing method is meaningful to improve the nursing quality and worth to be popularized. Key words: Oral nursing; Baby hand and mouth wet wipes; Effect observation

Comparison of Passive Flow Control Methods for a Cavity in Transonic Flow

A comparative study of different passive control techniques was conducted on a cavity with a length of 320 mm with length-to-depth and length-to-width ratios of five and two, respectively. The tests were conducted at a freestream Mach number of 0.71. Both leading-edge and trailing-edge modifications were included in the studies. Results from surface pressure measurements showed that leading-edge control techniques were more effective at suppressing cavity tone amplitudes than trailing-edge modifications. A square-tooth spoiler showed the greatest reduction in tonal amplitude (8.8 dB); however, a sawtooth spoiler showed the greatest reduction in overall sound pressure level (8.13 dB). Velocity measurements inside the cavity were made using particle image velocimetry for the clean cavity and the cavity with sawtooth spoilers. The results showed a reduction in momentum exchange between the freestream flow and the cavity when spoilers were used. This is proposed to be the main reason for the reduced tonal amplitudes.

Rare occurrence of cavitation of lung metastases following effective targeted therapy: A case report.

The metastasis of malignant tumors to the lung is relatively common; however, cavitation of metastases is extremely rare in clinical cases, and the various mechanisms are controversial. The majority of irregular metastatic cavities form naturally and are detected incidentally when patients are examined prior to any therapeutic measures. The current study presents the case of a lung adenocarcinoma patient with total cavitation of intrapulmonary metastases following effective targeted therapy at the First Affiliated Hospital of Nanjing Medical University. The morphological changes were followed up for three years. This patient presented thin-walled and smooth clean cavities, which provides an indication of the effectiveness of treatment.

Evaluation of scale-adaptive simulation for transonic cavity flows

Scale-adaptive simulations of transonic cavities with and without doors are presented in this paper. Results were compared with detached-eddy simulations for cavities with length-to-depth ratios of 5 and 7. The Mach and Reynolds numbers (based on the cavity length) were 0.85 and 6.5 × 106, respectively, and the grid sizes were 5.0 million for the clean cavity with doors-off and 5.5 million for the clean cavity with doors-on. Instantaneous Mach number contours showed that the shear layer broke down for both the doors on and doors off cases and that the flows had a high level of unsteadiness inside them. The two L/D ratios of cavities were seen to have similar acoustic signatures reaching maximum sound levels of 170 dB. Spectral analyses for the cavities without doors revealed that by changing the length-to-depth ratio from five to seven, the dominant acoustic modes at the front and rear of the cavities were shifted from the second and third modes to the first and second modes respectively. Proper orthogonal decomposition was used to reduce the data storage using modes constructed from flowfield snapshots taken at regular intervals.

Aeroacoustic Investigation of a Cavity with and without Doors by Delayed Detached Eddy Simulation

In the present study, an effort was made to numerically investigate rectangular cavity aeroacoustics with and without doors. The simulation was performed on an open cavity with an aspect ratio of 5:1:1 at Mach 0.85 using the delayed detached eddy simulation (DDES) approach based on the Spalart-Allmaras model. Two cavity configurations, a clean cavity and a cavity with doors, were modeled. The results obtained from the clean cavity were compared with the experimental sound pressure levels (SPL) and the root mean square for the pressures applied. Furthermore, comparisons of frequencies were made using a modified semi-empirical Rossiter formula. The simulation using DDES precisely predicted the pressure fluctuation and the results matched the experiment quite well. The SPLs at the rear of the cavity were much higher than those in the front due to the instability of the shear layer impinging on the rear wall. Comparisons of DDES for the clean cavity and the doors-on cavity revealed that the SPLs inside the cavity as well as the magnitude of tones are amplified by the side doors. The main focus of this investigation was to obtain a better understanding of the open cavity acoustic resonance phenomenon and investigate the effects of cavity doors on the SPL.