Position Of Cavity Research Articles

Functional and Anatomic Outcomes of Primary and Secondary Internal Limiting Membrane Transplantation in Large and Persistent Macular Holes

The gold standard therapy for full-thickness macular holes (FTMH) is vitrectomy (PPV) with peeling of the internal limiting membrane (ILM), gas tamponade of the vitreous cavity and postoperative face-down positioning. Nevertheless, eyes with large macular holes (> 400 µm) and surgical failures remain difficult to manage. Recently, ILM transplantation (ILM-TX) techniques were developed with acceptable results, advocating different mechanisms of hole closure: in such a setting, the ILM could serve as a scaffold for neuronal tissue in the pedicle ILM flap technique or the ILM could induce a contraction of the FTMH rims through shrinking of a folded ILM plug. This retrospective study evaluates the functional and anatomic outcomes following ILM-TX for large FTMH and failed FMTH surgery. Large holes (group 1) were treated by the pedicle flap and the plug technique. Persistent holes following vitrectomy and ILM peeling (group 2) were treated with the plug technique. All ILM-TX were performed under perfluorocarbon liquid (PFCL) with a subsequent silicone oil tamponade. In group 1 (6 eyes), three eyes had a free ILM graft and three eyes underwent a pedunculated ILM-TX. The mean best corrected visual acuity (BCVA, LogMar) before primary ILM-TX was 1.18 ± 0.54 with a mean initial hole size of 681 ± 106 µm and a photoreceptor defect (PRD) of 1829 ± 474 µm. Five of six eyes showed a postoperative anatomical macular hole closure (83%). The mean BCVA after a mean follow-up of 9.3 ± 5.1 months was 0.83 ± 0.31 after a free ILM graft and 0.95 ± 0.79 after a pedunculated ILM flap. The PRD reduced to 1781 ± 713 µm after a free ILM graft and 1148 ± 378 µm after a pedunculated ILM flap. In group 2 (7 eyes), all patients had failed initial macular hole surgery closure. Prior to free ILM-TX BCVA was 1.05 ± 0.41, the hole size was 433 ± 183 µm and PRD was 2012 ± 718 µm. After a mean of 9.6 ± 4.1 months following ILM-TX, in six of seven eyes the FTMH hole was closed (86%), BCVA improved to 0.53 ± 0.34 and the PRD shortened to 843 ± 291 µm. In most cases, with large FTMH or holes after failed vitrectomy plus ILM peeling, ILM-TX allows a hole closure. Functional outcomes show stabilization and sometimes even a slight improvement.

Classic versus uterine sound-sparing approach for insertion of copper T380A intrauterine device: A randomized clinical trial

Abstract Objective The current study compares the efficacy of the classic approach and the uterine sounding sparing approach (a new approach) for copper intrauterine device (Cu-IUD) insertion. Study design A randomized clinical trial. Setting Woman's Health Hospital, Assiut, Egypt. Materials and methods The current study was an open parallel randomized clinical study conducted in Assiut Woman’s Health Hospital, Egypt included women requesting Copper IUD insertion. Enrolled women were randomized into 2 groups; group I included women subjected to classic approach for Cu-IUD insertion and group II included women had Cu-IUD insertion using the uterine sound-sparing approach (USSA). This approach utilized transvaginal ultrasound (TV/US) for assessment of the uterine cavity length and position before IUD insertion without using uterine sounding. The primary outcome was the successful Cu-IUD insertion. Results 46 women were analyzed in group I and 46 in group II. The pain during IUD insertion and 5 min post-insertion was significantly lower in group II than group I (p Conclusions Cu-IUD can be inserted successfully without using uterine sound provided using TV/US prior to insertion. This method associated with less pain, greater women satisfaction during insertion with shorter duration.

Selective Interactions of Cyclodextrins with Isomeric 1,2,4-Thiadiazole Derivatives Displaying Pharmacological Activity: Spectroscopy Study

Complex formation of α-, β- and γ-cyclodextrins with 1,2,4-thiadiazole derivatives, which are structural isomers displaying an activity in the treatment of Alzheimer’s disease, was examined by the use of 1H NMR and UV-spectroscopy. Stability constants of the complexes formed between cyclodextrins and thiadiazoles in two different buffers (pH 1.2 and 7.4) were calculated and analyzed. The temperature dependences of the stability constants were used to evaluate the enthalpy and entropy changes of complex formation. It was demonstrated that selectivity of the interactions between cyclodextrins and isometric 1,2,4-thiadiazole derivatives is determined by the size of macrocyclic cavity and relative position of the side groups in the benzene ring of the guest molecules. Higher stability of the complexes in the acidic medium (pH 1.2) in comparison with the slightly alkaline solution (pH 7.4) is caused by the important role of surface interactions.

Analysis on Mode Transition in a Dual-Mode Scramjet Combustor

ABSTRACTAn ignition combustion test of different combustor configurations and different fuel equivalence ratios was carried out in a condition of total temperature at 880 K, total pressure at 8 atm, and Mach number of 2.0 in regards to dual-mode combustor. There are three combustor configurations that are dual-mode combustors with double cavity flame holder. Hydrogen is injected in the first cavity while kerosene is injected in front of the first cavity. Hydrogen, being a pilot flame, was the first to be ignited by the spark, then kerosene was ignited by hydrogen. After that, injection of hydrogen was stopped and sole kerosene was kept burning steadily. The distribution of other airflow parameters in the combustor was obtained by calculating with a 1D analysis method; the influence of combustor configuration and fuel equivalence ratio to combustion mode transition was analyzed. The results indicated that the gradual transition of combustion mode in the combustor from supersonic combustion mode to subsonic combustion mode was accompanied by increasing the fuel equivalence ratio. The disturbance arising from wall pressure rise of the combustor was gradually moved upstream. The subsonic combustion area in Model 2 was moved by 60 mm upstream when compared with that in Model 1, which was basically in conformity with the distance that the initial position of the first cavity in Model 2 was moved by 58 mm forward. When the fuel equivalence ratio was equal, the length of subsonic combustion areas in the two models was basically unchanged. In the case of combined combustion of hydrogen and kerosene, the pressure disturbance had been spread upstream and arrived at the entrance to the combustor; thus, the inlet Mach number condition of the entrance to the combustor was damaged. The damage to the condition of the entrance to the combustor was more serious to some extent in Model 2 due to antedisplacement of the first cavity when compared with that in Model 1.

Migrating pleural plaque in a patient with asbestos induced pleural disease: a case report

BackgroundHealth surveillance of formerly asbestos exposed individuals focus on early detection of asbestos related diseases, such as lung fibrosis (asbestosis), pleural plaques, mesothelioma and lung cancer in particular. One main concern is the early and clear identification of lesions with a high risk of malignant changes and their undelayed clinical work-up. False positive results may lead to unnecessary and often painful diagnostic interventions, which create high costs when applied to a large cohort and also may discredit the whole program. We describe an unusual presentation of a common lesion among asbestos exposed individuals, which has to our knowledge never been described before. Being aware of this pathological pathway may prevent inadequate clinical decisions with disadvantages for the patient. Underlying implications regarding health surveillance and the reading of CT-scans of the thorax are important for the management of formerly asbestos exposed individuals.Case presentationDuring follow-up of an asbestos exposed 72 year old former power plant worker with known pleural changes, a nodule located next to the left costophrenic angle was newly discovered on CT-scan. As the previous scan 1 year before did not show any changes in that area, a fast growing tumour was suspected and an immediate biopsy performed. The tissue showed the characteristics of a pleural plaque with no signs of malignancy. After carefully reviewing all previous radiographs a rounded opacity attached to the mediastinal pleura close to the oesophagus and slightly cranial to the position of the removed nodule could be discerned. That nodule had increased in size over several years and was no longer visible on the latest scan. It appeared that the originally slow growing plaque had migrated to the costophrenic angle some time before it was discovered in the latest scan thus imposing as a fast growing tumour.ConclusionsWe concluded that asbestos related pleural plaques can under special circumstances get separated from the pleura and migrate to another position in the pleural cavity. The case provides new insights in the development and properties of pleural lesions and may offer new options for the management of formerly asbestos exposed patients.

What are the six degree-of-freedom errors of a robotically-machined femoral cavity in total hip arthroplasty and are they clinically important? An in-vitro study

Errors during a robot-assisted THA may result in a femoral cavity with position and orientation different than planned. This can lead to a femoral component placement that inaccurately sets a patient's femoral anteversion (FA), femoral offset (FO), and vertical offset (VO). The objectives of this study were to determine the position and orientation errors of robotically-machined femoral cavities in six degrees of freedom and to determine how position and orientation errors translate into errors in the setting of FA, FO, and VO. After creating preoperative plans, robot-assisted THAs were performed on twelve cadaveric specimens. The position and orientation of the machined cavities were compared to those of the planned cavities to determine the errors in six degrees of freedom. Placement of femoral components into the machined cavities was simulated, and the differences in FA, FO, and VO between the simulated and planned component placement were computed. While bias (i.e. mean error) occurred for three of six degrees of freedom in femoral cavities machined by a robotic system, the root mean squared errors (RMSEs) when the placement of femoral component was simulated were limited to 1.9° for FA, 1.0mm for FO, and 2.1mm for VO and were clinically unimportant.

PERBEDAAN BENTUK DAN UKURAN RUGAE PALATINA ANTARA MAMAK DAN KAMANAKAN LAKI-LAKI SUKU MINANGKABAU DI WILAYAH LUHAK NAN TIGO

Forensic odontology in dentistry is used to identify victims. Several methods can be used, such as rugoscopy.
 Rugoscopy is a victim identification method by evaluating the palatal rugae. Rugoscopy is very advantageous due to its low cost, fast results and practical nature. Palatal rugae is protected from trauma and high temperature due to its internal position in the oral cavity. Palatal rugae is an individualistic structure, though it bears several resemblance with the hereditary pattern due to the polygenic mechanism. The purpose of this research is to determine the difference of palatal rugae shape and size between uncle and nephew in Minangkabau ethnics. This study is an analytical observational study with a cross sectional approach. A total of 78 pairs of uncle and nephew of the Minangkabau ethnicity in Luhak Nan Tigo. Palatal rugae is classified using the Thomaz and Khutze classification. Data were analyzed by using Mann Whitney non-parametric statistical analysis. Data analysis show the palatal rugae shape of uncle and nephew from the Minangkabau ethnicity is dominated by a wavy shape, followed by curvy, straight, unified and circular shapes. The palatal rugae size of uncle and naphew from the Minangkabau ethnicity is dominated by primary size, followed by secondary and fragmenter size. Mann Whitney analysis revealed no significant difference of palatal rugae shape and size between uncle and nephew in Minangkabau ethnics (p>0,05), though there is a significant difference in the unified shape (p<0,05). Palatal rugae shape and size have a similar pattern with hereditery patterns, though not identical. Palatal rugae may be used as a secondary method of victim identification
 Keywords : Rugoscopy, palatal rugae, uncle and nephew

Presurgical orthopedics in patients with unilateral cleft lip and palate: clinical case reports

ABSTRACT The attention of patients with cleft lip and palate on the basis established by McNeil, Burston, Hotz, Gnoinski among others is hereby presented using a stimulating palatal obturator with 10 patients of the Orthodontics Service at the Children's Hospital of Mexico «Federico Gomez». Two patients didn’t return and one died before the second appointment. The benefits of presurgical orthopedics were observed, improving the patient's functional and physical appearance, such as swallowing, tongue position in the oral cavity, improvement in the relationship of the maxillary segments and narrowing of the fissure. Following the protocol established by the Children's Hospital of Mexico «Federico Gomez» based on the Zurich approach (McNeil, Hotz, Burston, Gnoinski, et al), the procedure resulted suitable for surgical preparation of palatoplasty and cheiloplasty in patients with unilateral cleft lip palate.

Portable Video Electronic Anus Diagnosis Instrument Based on DaVinci Technology

In order to overcome large volume, no light, blind into the mirror, unable to locate faults, easily misdiagnosed of the common anal diagnosis instrument, multifunctional portable video electronic anus diagnosis instrument is developed. DaVinci technology is applied in medical video development. Electronic anus diagnosis instrument includes micro camera, LED light source, display device, DaVinci chip, etc. A LED lamp aperture in the inner wall of the tube can increase the clarity of the image. The lower end of the handle is provided with a scale anoscopy, which can be prepared to judge the position and the range of the disease, so as to improve the accuracy of the examination. Portable electronic anal diagnosis instrument is portable, visible and can be located. It can observe the multi position of the inner cavity of the anus and the wall of the rectum with real-time record store image and high quality of image acquisition. It provides new technology for the diagnosis and treatment of anorectal deep source of disease.

Effects of convex cavity structure, position and number on conversion of methane catalytic combustion and extinction limit in a micro-channel: A numerical study

The micro-channel combustion increasingly plays a significant role in Micro-Electro-Mechanical System (MEMS). The numerical investigation has been carried out in a micro-channel with detailed reaction mechanism. Also, an effective method has been identified to improve methane conversion efficiency. Moreover, the extinction limit of premixed methane/air catalytic combustion has been determined with the presence of a convex cavity. And, the effects of four factors for normalized cavity length, normalized cavity diameter, position, and number of convex cavities on the catalytic combustion characteristics of methane/air in a micro-channel have been investigated with numerical method, respectively. Comparison of the above four factors, increasing the normalized cavity diameter of the convex cavity is the most effective way to improve methane conversion ratio and expand extinction limit. The results also show that a vortex street in the channel appears with normalized cavity diameter of 0.3, the recirculation zone and vortex street zone in the channel improve the stability of combustion. Besides, the methane conversion ratio can be increased to 90.3% and the extinction limit can be reached up to 18.9m/s at normalized cavity diameter of 0.3. This study provides some useful information for the design and operation of the micro-combustor with convex cavity.

The influence of cavity parameters on the combustion oscillation in a single-side expansion scramjet combustor

Cavity has been validated to be efficient flameholders for scramjet combustors, but the influence of its parameters on the combustion oscillation in scramjet combustor has barely been studied. In the present work, a series of experiments focusing on this issue have been carried out. The influence of flameholding cavity position, its length to depth ratio L/D and aft wall angle θ and number on ethylene combustion oscillation characteristics in scramjet combustor has been researched. The obtained experimental results show that, as the premixing distance between ethylene injector and flameholding cavity varies, the ethylene combustion flame will take on two distinct forms, small-amplitude high frequency fluctuation, and large-amplitude low frequency oscillation. The dominant frequency of the large-amplitude combustion oscillation is in inverse proportion to the pre-mixing distance. Moreover, the influence of cavity length to depth ratio and the aft wall angleθexists diversity when the flameholding cavity position is different and can be recognized as unnoticeable compared to the impact of the premixing distance. In addition, we also find that, when the premixing distance is identical and sufficient, increasing the number of tandem flameholding cavities can change the dominant frequency of combustion oscillation hardly, let alone avoid the combustion oscillation. It is believed that the present investigation will provide a useful reference for the design of the scramjet combustor.

Abstract OT2-03-02: Feasibility of assessing radiation response with MRI/CT directed preoperative accelerated partial breast irradiation in the prone position for hormone sensitive early stage breast cancer

Abstract Background: Accelerated partial breast irradiation (APBI) delivers adjuvant radiation (RT) to the 1-2 cm of the breast at highest risk for recurrence surrounding the lumpectomy (L) cavity over 5-8 days and is an alternative to standard whole breast irradiation for hormone sensitive (HS) stage 1 (T1, N0) breast cancer (BC) based on 2 randomized controlled trials. External beam methods for APBI are common but have notable inherent drawbacks that include: inter-fraction inaccuracy due to patient setup based on anatomy, intra fraction error related to patient or respiratory motion, and inaccurate geometric targeting by relying on L cavity position instead of the tumor position. Postoperative RT has other limitations including delivery in the setting of disrupted blood or lymphatic supply that may be suboptimal for radio sensitivity and it eliminates observation of radiation-induced tumor response. MRI is an established tool for measuring BC extent and response from neoadjuvant systemic therapy. It's hypothesized that MRI directed pre-operative APBI using intensity modulated radiotherapy (IMRT) with image guidance (IGRT) will improve RT delivery, and that MRI features can be identified to correlate with pathologic radiation response. Trial Design: There are 2 cohorts to this single arm prospective trial. The first cohort is for establishing and verifying patient flow and image fusion between MRI, CT and RT planning. In the second cohort eligible patients will receive preoperative APBI 38.5 Gy in 10 fractions BID with IMRT, IGRT in the prone position using MRI defined targets fused to CT treatment planning. Eligibility: For cohort 1 it is HS Stage 1 BC that has completed CT in prone position for RT planning. Eligibility for cohort 2 requires: age > 60 yo, clinical stage 1 BC, HS, HER2 negative, intending L, clinically negative axilla verified by ultrasound, able to tolerate the prone position, and MRI with contrast. Specific aims: To determine the reproducibility of MRI directed preoperative APBI based on meeting 3 criteria: ability to define RT targets by MRI, quality of RT plans and completion of treatment (APBI and surgery). Additional aims include assessing toxicity, cosmetic outcome, local regional cancer control and collection of tissue for correlative studies. Statistical methods: The optimal two-stage design by Simon is used. Sample size for cohort 2 is based on the first endpoint. 19 eligible patients will be required in the first stage; if 3 or more treatments are scored unacceptable, then early stopping will be recommended. Otherwise, accrual will continue to a total accrual of 30. If > 4 of 30 treatments are scored unacceptable, the technique will be considered not reproducible, and a Phase II study will not be pursued. Under the null hypothesis of an 80% reproducibility rate, this two-stage design has an expected sample size of 24.4. Patient accrual to cohort 1 is 2 and targeted accrual is 3. Patient accrual to Cohort 2 is 0 and targeted accrual is 30. Contact information: Soyhun Mc Elroy ( Sohyun.McElroy@osumc.edu) or Julia White (Julia.White@osumc.edu) Funding source: Susan G Komen Breast Cancer Foundation Grant # GRT00035216. Citation Format: White J, McElroy S, Seykon A, Wei L, Bazan J, Yang X, DiCostanzo D, Gupta N, Knopp M. Feasibility of assessing radiation response with MRI/CT directed preoperative accelerated partial breast irradiation in the prone position for hormone sensitive early stage breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT2-03-02.

The influence of chest tube size and position in primary spontaneous pneumothorax.

Optimal chest tube position in the pleural cavity is largely unexplored for the treatment of primary spontaneous pneumothorax (PSP). We investigated whether type, size and position of chest tubes influenced duration of treatment for PSP. A retrospective follow-up study of all patients admitted with PSP over a 5-year period. Traumatic, iatrogenic and secondary pneumothoraxes were excluded. Gender, age, smoking habits, type and size of chest tube used (pigtail catheter or surgical chest tube) were recorded from the patients' charts. All chest X-rays upon admittance and immediately following chest tube placement were retrieved and re-evaluated for size of pneumothorax (categorized into five groups) and location of the chest tube tip (categorized as upper, middle or lower third of the pleural cavity). All data were analysed in a Cox proportional hazards regression model. We identified 134 patients with PSP. Baseline characteristics were similar for patients treated with surgical chest tubes and pigtail catheters. Chest tube duration was not significantly influenced by position of the chest tube tip, but was significantly longer in females (P<0.01), patients <30 years (P=0.01), larger pneumothoraxes (P<0.01), use of surgical chest tubes (P=0.03) and a history of previous pneumothorax (P=0.04). Contrary to common belief and guidelines recommendation the position of a chest tube in the pleural cavity did not significantly influence chest tube duration, but it was significantly longer in patients who were treated with a surgical chest tube.

Secretory spaces in species of the clade Dipterygeae (Leguminosae, Papilionoideae)

Dipteryx, Pterodon and Taralea are legume genera known for secreting oils, produced in secretory canals and cavities, with medicinal properties. We analyzed the distribution, morphology and histochemistry of these glands in leaves and stems of Dipteryx alata, Pterodon pubescens and Taralea oppositifolia, three Neotropical species, using standard techniques for anatomy and histochemistry. Secretory spaces, i.e. secretory cavities and canals, exhibited a wide lumen and a single layer of epithelium. Digitiform epithelial cells, forming trabeculae protruding into the lumen, were seen in all three species. Secretory cavities with a rounded or oval lumen and secretory canals with an elongated lumen in longitudinal sections were found only in T. oppositifolia. In D. alata and P. pubescens, only secretory cavities were found. In P. pubescens, secretory cavities occurred in the leaf blade margin. In T. oppositifolia, secretory spaces were much more numerous than in the other two species. Terpenes, total lipids, phenolic compounds, alkaloids and polysaccharides were detected in the secretory spaces of the three species. The abundance of secretory spaces, the presence of canals in T. oppositifolia and the position of cavities in P. pubescens are features with potential diagnostic value for their respective genera.

Plasmonic-induced absorption in an end-coupled metal-insulator-metal resonator structure

An end-coupled composite-slot-cavity resonator (CSCR) is proposed based on the subwavelength metal-insulator-metal (MIM) waveguides. When compared with the perfect slot cavity, which acts as a Fabry–Perot resonator, plasmonic-induced absorption effect is achieved in the CSCR system. Single or dual absorption windows will arise at the former transmission peaks by arranging the position of vertical-slot cavity in the CSCR. According to the analyses on the phase responses, abnormal dispersions will be achieved inside the windows. Therefore, one can manipulate the fast-light applications in the nano-scale integrated circuits. Furthermore, based on the same interference effect, plasmonic-induced transparency response with normal dispersion is also obtained by changing the end-coupled CSCR system to a side-coupled one. The performances of the proposed structure are analyzed and investigated using the coupled mode theory and the finite-difference time-domain method, respectively.

Tooth eruption disorders associated with systemic and genetic diseases: clinical guide

Tooth eruption is defined as the movement of the dental root and the tooth from its original development site in the alveolar process to its functional position in the oral cavity. Despite vast amounts of research, the exact mechanism of tooth eruption remains unknown. The authors have shown that the dental crown is not necessary for tooth eruption, whereas the dental follicle seems to be essential for the process. The formation of an eruption pathway by bone resorption allows the root to breach the oral cavity, at the same time, bone formation occurs at the basal level of the dental root. Multiples genetic and molecular structures coordinate these events. Sometimes it is by studying pathological conditions that we discover the essential interactions that occur during tooth eruption. Frequently, a delayed tooth eruption (DTE) is the first, if not the only, expression of a local or general pathology. A DTE can affect directly the diagnosis, the treatment planning, or the timing of the orthodontic treatment. Therefore, it is essential for the orthodontist to identify the cause of a DTE for implementing the correct treatment.

The Impact of Housing Features Relative Location on a Turbocharger Compressor Flow

This work presents an investigation on a flow phenomenon marked by in-plane velocity non-uniformity associated with a ported shroud turbocharger compressor observed upstream of the compressor inlet at lower operating speeds. The effect of structural struts in the ported shroud (PS) cavity and the location of the volute tongue on velocity non-uniformity is studied in this paper by numerically modelling the complete compressor stage using a (Un)steady Reynolds Averaged Navier-Stokes (RANS & URANS) approach. The results show that the amplitude of in-plane velocity non-uniformity is reduced by removing the struts from the PS cavity. Furthermore, the change in location of the volute tongue is shown to either substantially diminish or enhance the amplitude of velocity non-uniformity based on the relative position of the volute tongue and the struts. The study concludes that the velocity non-uniformity is dependent on the coupled effect of volute tongue and the strut position in the PS cavity.

Topology optimization of anechoic coating for maximizing sound absorption

Anechoic coatings, attached to the surface of underwater vehicles, are an effective way to absorb the incident sound from active sonars. It is well known that a homogeneous viscoelastic material layer with limited thickness does not provide significant sound absorption performance, thus, anechoic coatings embedded with air cavities are being used for underwater applications. Previous optimization works on this type of anechoic coating mainly focused on the geometrical parameters, position and shape of the internal cavity, while ignoring the influence of the material distribution configuration. In this research, we propose a topology optimization formulation that can directly determine the optimal material layout. A method combining the Bloch theory and finite element method (FEM) is adopted to analyze the sound characteristics of a unit cell model, which is able to represent the whole periodic structure. The proposed optimization formulation employs a reflection coefficient to form the objective function under zero transmission backing conditions. Sensitivity analysis is explicitly presented for the utilization of the typical gradient based optimization method. Finally, numerical examples are provided to demonstrate the validity and significant enhancement in the absorptive performance of anechoic coatings achieved by the proposed methodology. The influence of material distribution on macro level and further research emphases on low frequency reduction are also discussed.

Comparison of wetting models and geometrical analysis in describing the effect of cavity number, size, and position on apparent contact angle

A critical subject of surface science is whether contact area or the triple-phase contact line (TPCL) directly affects the apparent contact angle (APCA). On this premise, effect of cavity size and position on APCA is studied. Cavities were created using a laser machining process. Optimal conditions for laser patterning were obtained via trial and error. It was impossible to deposit a droplet that could rest on all of the cavities for about 0.16 mm distance between the edge of the patterns and the drop’s perimeter. Neither Wenzel nor Cassie–Baxter models can fully explain the acquired data from static contact angle measurements. Revised Cassie–Baxter equation also fails, while a simple geometrical analysis based on Spherical Cap assumption shows a better agreement with the data as long as the cavities are sufficiently far from TPCL. Based on our results, we believe that theoretical analyses regarding wetting models are not in line with engineering aspects of wetting which should be focused on TPCL.

Numerical investigation on shock train control and applications in a scramjet engine

Different factors which help to control the shock train in the scramjet isolator and combustor were analyzed via numerical investigations, and were applied to a whole scramjet engine in the working environment. A streamline traced Busemann inlet is proposed and simulated along with an isolator. During the combustor design, the influence of boundary layer thickness, slot bleeding, cavity and hydrogen injection position on the basic combustor performance with uniform inlet flow condition are investigated, and it was found that the boundary layer bleeding could prevent the shock train from moving upstream, and the cavity could further enhance the combustion efficiency. By arranging hydrogen injections at certain intervals, it could reduce the combustion back pressure. An improved basic model by integrating the aforementioned advantages is then numerically studied. The results have shown that the improved combustor model contained a section of shock train which can reduce the loads on the isolator. Another model with bleeding slots in the isolator is also found able to raise the maximum chemical equivalence ratio from 0.7 to 1, but unfortunately it comes with undesirable combustion efficiency decrease.