Groove Area Research Articles

Highly sensitive threaded LPFG strain sensor

Long Period Fiber Grating (LPFG) strain sensors have been used to monitor the structural health of bridges and buildings, and there is a need to further improve their sensing sensitivity. This article proposed a threaded LPFG strain sensor, which used a CO2 laser to etch a long groove at the top of the cladding of a single-mode fiber. The fiber in the long groove area was heated and twisted to fabricate a long period fiber grating (TH-LPFG) strain sensor with a threaded groove on the cladding. When strain is applied, the strain is concentrated in the threaded area on the cladding, increasing and decreasing the effective refractive index changes of the cladding mode and core mode respectively, achieving enhanced strain sensing. The experimental outcomes demonstrate that the TH-LPFG strain sensor achieves a sensitivity of 44.9 pm/µε to strain, while its cross-sensitivity to temperature is minimal, at just 1.28 µε/°C. TH-LPFG provides a new solution for enhancing the sensitivity of LPFG strain sensing, with low production cost and low temperature crosstalk. It can be used in the field of highly sensitive strain monitoring of building structures.

Exploring the interplay between epicardial fat, coronary artery calcium score, and nonalcoholic fatty liver disease through non-ECG-gated chest computed tomography: A cross-sectional study.

This study examines the relationships between epicardial adipose tissue (EAT), nonalcoholic fatty liver disease (NAFLD), and coronary artery calcium score (CACS) using non-ECG-gated CT scans. It aims to determine the effectiveness of EAT measurements and NAFLD as predictors for coronary artery disease (CAD). This cross-sectional study was conducted at a specialized center, focusing on individuals who underwent non-ECG-gated chest CT scans without contrast. We evaluated EAT thickness and density in three areas: the right atrioventricular groove, the free wall of the right ventricle, and the central area of the right anterior interventricular groove. Additionally, we measured CACS and determined the presence of NAFLD by comparing liver-to-spleen density ratios. Statistical analyses, including regression models, were performed using SPSS (version 26). In this study, we enrolled 365 participants, including 203 males with an average age of 47 ± 17.93 years. EAT thickness was 6.28 ± 1.62 mm, and EAT density was -96.07 ± 12.47 Hounsfield units (HU). The mean CACS was 22.27 ± 79.01, and the mean liver density was 50.01 ± 10.76 HU. A significant positive correlation was observed between EAT thickness and CACS (r = 0.208, p < 0.001). EAT density showed a significant negative correlation with CACS (r = -0.155, p = 0.003). No correlation was found between NAFLD and CACS. Univariate logistic regression analysis identified significant predictors of increased CACS, including EAT thickness (OR: 1.803), EAT density (OR: 0.671), diabetes mellitus (DM) (OR: 5.921), and hypertension (HTN) (OR: 7.414). Multivariate analysis confirmed the significance of EAT thickness (OR: 0.682), DM (OR: 3.66), and HTN (OR: 2.79) as predictors of elevated CACS. Our findings demonstrate that increased EAT thickness and decreased density are associated with higher CACS. Also, both DM and HTN significantly contribute to increased CACS. These results support the inclusion of EAT measurements in cardiovascular risk assessment models to enhance diagnostic accuracy.

Influence of AWJ Process Parameters on Erosion Groove Formation in Additively Manufactured Stainless Steel.

The presented manuscript focuses on the influence of process parameters of abrasive water jet technology on the creation of non-transient erosive grooves. The processed stainless steel SS 316L is additively manufactured using the selective laser melting (SLM) method. Due to the distinct mechanical properties of this material resulting from the production process, the material was machined in two planes according to the direction of the printing layers. The experimental part employed a planned experiment utilizing the DoE (Design of Experiment) method. Experiments aimed at varying process parameters (traverse speed, standoff distance, abrasive mass flow) were conducted at a water pressure of 50 MPa, assessing the parameters' impact on the removed material and the properties of the resulting non-transient erosion groove. The properties of the erosion groove, such as shape and the material removal (area of erosion groove), were evaluated. The influences of process parameters on the observed parameters were assessed using the analysis of variance (ANOVA) method. Experiment preparation and setup were based on a thorough theoretical analysis of the machining process with the abrasive water jet (AWJ) method. The experiment also highlights the diverse properties of the SS 316L material prepared using the SLM method when machined with AWJ technology.

Histological features of the structure of the long head of biceps brachii tendon in patients with concomitant injuries of the rotator cuff

Background. The long head of biceps brachii tendon plays an important role in shoulder pain. Surgical tactics remain controversial. There are two approaches: tenotomy of the long head of biceps brachii tendon and tenodesis. Both have positive and negative sides. There is also no consensus on the effective position for performing tenodesis.The aim. To assess the histological structure of various parts of the long head of biceps brachii tendon, which may be the causes for persistent pain syndrome.Materials and methods. In this study, we examined the histological structure of the long head of biceps brachii tendon in 12 patients aged 18–59 years having chronic anterior shoulder pain with concomitant damage to the supraspinatus and subscapularis tendons. In all cases, magnetic resonance imaging (MRI) revealed changes that made it impossible to perform intraarticular tenodesis. Patients were divided into two groups according to the World Health Organization classification: young (18–44 years) and middle-aged (45–59 years). All patients underwent arthroscopy with subpectoral tenodesis and correction of concomitant pathology. The obtained macropreparations are divided into three zones: the proximal zone, the intertubercular zone and the zone below the intertubercular groove. All macropreparations were sent for histological examination.It was revealed that the most common changes occur in the area of the intertubercular groove in all categories, however, in the middle-aged group, the signs of inflammation and degeneration are equally evident in this zone and in the proximal part of the tendon.Conclusions. Young and middle-aged patients with damage to the tendons of the supraspinatus and subscapularis muscles and signs of chronic tendinitis of the long head of biceps brachii tendon tendon and pronounced structural changes according to MRI should undergo a subpectoral tenodesis procedure; it is also necessary to take into account the anatomical features of the tendon and possible surgical risks.

Scratch resistance of glass‐basalt fiber reinforced epoxy hybrid composites: A comparative study

AbstractThis research explores the scratch resistance of polymer composites reinforced with hybrid glass and basalt fibers under repeated loadings. By examining the behavior across 1–10 repetitions using Rockwell and Vickers indenters, the study delves into the complex interplay between composite matrices and the fibers' configurations. Through Scanning Electron Microscope (SEM) imaging and 3D profilometry, it reveals how different fibers influence the composite's surface post‐scratch tests. Basalt fibers are found to offer superior scratch protection over glass fibers, although both types' of effectiveness declines with increased loading cycles, showing significant material loss and surface damage respectively. Composites with these fibers display enhanced resistance, especially when basalt fibers are optimally positioned on the surface. The study underscores the critical role of fiber‐matrix bonding in scratch resistance and the significant impact of mechanical stress. It was found that the scratch hardness values reduced with more repeats in the scratch tests utilizing Vickers and Rockwell indenters. The sample with the label G4B6G4 has the greatest hardness values, which is noteworthy. After 10 repeats, the scratch hardness values for this sample reduced to 225 N/mm2 and 75 N/mm2, respectively, from roughly 340 N/mm2 and 225 N/mm2 at both ends for a single repetition. In addition, ANOVA for penetration depth is dominated (66.01%) by the repetition factor. The most common kind is indenter (42.79%), with low p‐values. Despite material and indenter effects, groove area study confirms the significance of repetition (65.72%).Highlights Basalt fibers enhance scratch resistance more than glass fibers. Increased scratch repetitions lead to fiber breakage and material loss. Hybrid fiber layers distribute load and minimize surface damage. Strong fiber‐matrix adhesion is crucial for reducing damage severity. Research informs the design of durable, fiber‐reinforced composites.

Ultimate water level and deformation failures of the artificial dam in the coal mine underground reservoir

Coal mine underground reservoirs provide a new choice for the protection and utilization of water resources. This paper takes the underground reservoir of Wulanmulun Mine as the background, and takes the MB-1# artificial dam in the goaf of 31104–31116 working face of 3–1 coal seam as the research object. The theoretical model of artificial dam is established by elastic–plastic two-way slab theory, and the theoretical mechanical analysis and calculation are carried out. A similitude physical model for the coal mine underground reservoir was built by using the self-developed nested dual-dynamic-pressure similitude simulation testing system. Later, the mechanical response and deformation failure features of the artificial dam under different water pressure values were analyzed and the ultimate water pressure was determined. In addition, FLAC3D was used to determine the stress-seepage field-coupling model for the artificial dam. Using this model, the influence of water pressure on the multi-load coupling effect of the artificial dam and coal pillar dam was characterized. The dam form is optimized and the safety water level evaluation method of the dam body is proposed. The research results are as follows: (1) Based on the theory of elastic–plastic two-way slab, the theoretical analysis model of artificial dam is established, the expression of the ultimate water level function of artificial dam is derived, and the theoretical ultimate water head is determined to be 18.2 m (2) The seepage law of underground reservoir under different water pressures is obtained, and the ultimate water pressure of the model is determined to be 11.43 kPa. (3) It is clarified that the failure modes of the artificial dam are seepage failure and mechanical failure, and it is revealed that the groove area is the weakest position where the dam is most vulnerable to failure. In view of the failure modes of the dam, the I-shaped structure artificial dam is proposed. (4) A safe water level assessment method is proposed for the constructed artificial dam. According to the analysis of on-site monitoring data of MB-1# dam, the actual water level in the reservoir is within the allowable water level range of the artificial dam, and the whole reservoir is in a stable and relatively safe state at present. The reliability of this assessment method has been verified.

The evolution of the compaction process and the deformed state of porous blanks during their hot forging in the open die

The article presents the results of the study of the evolution of the deformed state of the workpieces, the energetic parameters of the process and the distribution of porosity over the volume of the forging at all stages of hot forging of porous powder forgings in an open die. Modeling of the process was carried out using the finite element method using the DEFORM 2D/3D software complex. As a result of the simulation, it was found that at the initial stage of the process, the blank is mainly compacted with minimal radial flow of the material. Noticeable flow of metal into the groove groove area begins only when the forging material reaches an average relative density exceeding 90%. A significantly different nature of the distribution of axial er and radial ez deformations over the volume of the forging was noted. A zone with increased levels of values of axial deformations is formed in the central layer of the forging, equidistant from the upper and lower surfaces of the die cavity, and the values of radial deformations decrease with distance from the zone bordering the free side surface of the workpiece in the radial (to-center) direction. The minimum values of ez and er appear in the upper and lower angular stagnant zones of the forging. It is shown that the graph of the dependence of the deformation force on the displacement of the punch is marked by the presence of at least three characteristic sections due to the relationship between the processes of compaction and forging shape change at each stage of the process.

Half-precast “crossbar-slab-column” frame joint

Introduction. Half-precast frames embodied the positive properties of both precast and cast-in-situ structures. These structural systems are difficult to introduce due to their low level of knowledge, lack of experimental data, and an almost complete absence of a regulatory and technical framework for a design. This stimulates a need to improve and develop new joints with high operational reliability and manufacturability.Aim. To identify the causes of the frame joint destruction.Materials and methods. The frame joint is provided by the hidden cast-in-situ column cantilever in the grooves of crossbars and half-precast floor slab with the installation of additional longitudinal and transverse reinforcement. Precast and cast-in-situ elements interact mainly by reinforcement starter bars. The destruction of frame joints was considered using the example of a half-precast frame with the main spans of 9 and 12 m in a two-storey building according to the results of a full-scale survey during the construction period.Results. At the joints of most crossbars with columns, inclined cracks were detected in the support zones along the lateral surfaces with an opening width of 0.1–5 mm. In addition, cracks were observed along the contact area of the support crossbar groove with the column grouting concrete. An opening revealed them spreading into the body of the groove grouting concrete along the column edge. No adhesion between the walls of a crossbar groove with the joint grouting concrete is observed. The crack formation pattern indicates the determined contour of the floor slab punching above the column.Conclusion. The cause for the destruction of half-precast frame joints involves the insufficient bearing capacity of the section for the action of transverse forces due to the ductility of precast and cast-in-situ elements.

Evolution and Action Mechanism of Relative Negative Pressure Zone in Spiral Groove Gas Face Seal for Aero-Engine

Abstract As an advanced sealing technology, the application of gas face seal in aero-engine is few; if possible, lower specific fuel consumption, higher thrust-weight ratio, and effective secondary flow control at minimal cost would be brought. A relative negative pressure zone (RNPZ) was found in the spiral groove gas face seal, and the evolution and action mechanism of RNPZ was investigated in detail, which may promote the above application. Three film thicknesses of spiral groove gas face seals at different rotational speeds and inlet pressures were numerically compared to obtain the pressure field in the groove area and the formation of RNPZ. Then, the radial and circumferential velocities in the groove were calculated to quantify the impact of the obstruction effect, viscous pumping, and shear effect, which revealed the evolution mechanism of the RNPZ stage by stage. At last, the action mechanism of RNPZ was clarified through the hydrodynamic performance analysis. It is found that the pressure field evolution in the gas face seal is in stage Ⅲ under the high rotational speed and low inlet pressure conditions in an aero-engine. Under the same film thickness, RNPZ can suppress leakage to a certain extent in stage Ⅱ, while in stage Ⅲ, it increases the opening force and stiffness-leakage ratio. This work can provide theory and data to help with the subsequent optimization design of gas face seals for aero-engine.

Effect of Groove Structure on Lubrication Performance of Water-Lubricated Stern Tube Bearings

This study investigated the lubrication characteristics (i.e., the groove ratio and width) of water-lubricated stern tube bearings, based on the flexibility matrix method and lubrication theory. Considering the elastic deformation of the lining, a fluid structure interaction (FSI) model of the surface micro-groove texture of a water-lubricated stern tube bearing was established, and the correctness and rationality of the model were verified by experiments. Micro-grooved, surface-lubricated, water-lubricated stern tube bearings with three different cross-sectional shapes (rectangular, circular, and triangular) were designed. The influences of the groove area ratio and width on the bearing load-carrying capacity and friction coefficient were analyzed. At a groove area ratio of 0.31, the load-carrying capacity of the rectangular grooved stern tube bearing reached the maximum value and the friction coefficient reached the minimum value. It is recommended to design and use water-lubricated stern tube bearings, especially Thordon water-lubricated stern tube bearings, with rectangular micro-grooves, with a groove area ratio of 0.30–0.32, so that the best lubrication performance can be obtained. With the increase in the micro-groove width, the lubrication of water-lubricated stern tube bearings with partial rectangular micro-grooves is significantly better than that of others. Under the same conditions, the bearing load-carrying capacity and friction performance of local groove stern bearings is significantly better than that of global groove stern bearings.

Tribological behavior of the friction film of polycrystalline diamond compact and different matching materials in drilling fluid

The tribological properties of polycrystalline diamond compact (PDC) with different matching pairs (Al2O3, ZrO2, and GCr15 balls) in drilling fluid were studied. The friction coefficient, microstructure, wear rate, three-dimensional surface morphology, and transfer behavior of the friction film of different balls and PDC were analyzed experimentally. The results showed that there are significant differences in friction and wear behavior between PDC and different balls in the drilling fluid environment. In addition, the surface of PDC will form a friction-protective film in the presence of drilling fluid. Different friction pairs exhibit different degrees of damage to the protective film and form a transfer film during the friction process. When the protective film on PDC is destroyed, small particles in the drilling fluid can fill the groove area to repair and prevent further friction and wear.

O146 Natural history and clinical outcomes in patients with groove pancreatitis: an observational study

Abstract Introduction Groove pancreatitis (GP) is a rare and focal form of pancreatitis affecting the para-duodenal groove area. Diagnosis is usually made by radiological imaging or histological analysis. This study aimed to determine the disease pattern, treatment modalities and outcomes. Methods Data were retrospectively collected for patients diagnosed with GP radiologically and/or histologically at our tertiary hospital from 2010 to 2019. A search of our imaging database was conducted using the term groove pancreatitis totalling 1,040 patients. Duplicates (95) and reports mentioning only groove or only pancreatitis (945) were eliminated. All included patients were then re-assessed by two expert hepatopancreaticobiliary radiologists and a specialist histopathologist to confirm inclusion. Results Our cohort comprised of 54 patients, 39 males and 15 females. The mean age was 67 years (range 39-101 years). Of the 54 patients, 11 had pancreatic cancer (20%). Pain as a main presenting complaint occurred in 78% and jaundice in only 13%. 26% had elevated lipase and 37% had deranged LFTs. 69% were managed conservatively as first line. 11% of patients failed conservative management and proceeded to endoscopic treatment. Surgical intervention occurred in 24%. 11% of all patients had complete symptom relief, and 76% showed symptom improvement. Mortality at 2years of follow-up, was 45% and 28% in those with and without cancer. Conclusion GP is a benign disease with a non-specific natural history. It remains unclear if there is a transition between GP and GP-associated mass. This emphasises a high index of suspicion in diagnosis, using radiological, endoscopic, and cytological analysis.

Design of evanescent mode band-pass filters based on groove gap waveguide technology

This paper proposes for the first time a design method of Chebyshev band-pass filters based on groove gap waveguide (GGW) technology and evanescent mode. The evanescent mode GGW section has been implemented by decreasing the width of the groove area by means of two additional rows of metallic pins, and the filter structure has been obtained by inserting resonators of metallic pins along the central part of this narrower GGW section according to a coupling matrix synthesis method. The proposed method has allowed reducing the analysis number of this band-pass filter during the design process and the computation cost with the electromagnetic (EM) simulator, solving the discretization problem of the different lengths of the evanescent mode section. This design technique has been applied to a fourth-order Chebyshev band-pass GGW filter. The design has been performed in the recommended band of the WR75 standard (10 GHz – 15 GHz). The design specifications have been a central frequency f0=12 GHz, a fractional bandwidth FBW = 2.5 % and return loss RL = 20 dB. Measurement and electromagnetic (EM) simulation results have shown a good agreement. Return and insertion losses in the pass-band region of the measured prototype have been, respectively, RL = 20 dB and IL = 0.3 dB, while maximum attenuation in the stop-band regions reached ASB = 83 dB. A comparison has been performed between the measured prototype and other GGW band-pass filters. The proposed GGW band-pass filter has been shown to have reduced size and high-performance characteristics. Future emerging communications systems could benefit from this evanescent mode GGW Chebyshev band-pass filter.

Experimental Investigation on Performance Characteristics of Dry Centrifugal Clutch with Grooved Friction Liners

The deteriorated condition of friction liners after prolonged use is one of the primary causes of judder in centrifugal clutches. The friction characteristics can be retained by generating specific textures or grooves on the friction liner. An attempt has been made to study the characteristics of centrifugal clutch using grooved friction liners. A test cycle for centrifugal clutch has been developed using a number of engagements as the basis. A vehicle test bench was used for the experiment where the developed test cycle was automated. The performance characteristics of the centrifugal clutch have been recorded and analyzed with normal friction liners and grooved friction liners for 100 test cycles. For this study, the groove area ratio was retained at 0.15, and the grooves were cut at 90°. After completing 100 test cycles, the clutch with a grooved friction liner exhibited better characteristics. After completing 100 test cycles, the surface roughness reduction at the leading section of the grooved friction liner and normal friction liner has been found to be 6.44% and 8.11%, respectively. The thickness reduction at the leading section of the grooved friction liner and normal friction liner has been reported to be 3.73% and 4.98%, respectively. Throughout the run of 100 test cycles, the higher clutch housing temperature has been witnessed in the case of a clutch with a grooved friction liner. At the 100th test cycle, the clutch torque with a grooved friction liner was 15.22% more than the clutch torque with a normal friction liner. Even after prolonged use, the clutch with grooved friction liner exhibited better judder characteristics and also provided higher fuel economy for vehicles.

Groove Pancreatitis-Tumor-like Lesion of the Pancreas.

Groove pancreatitis (GP) is an uncommon appearance of pancreatitis represented by fibrous inflammation and a pseudo-tumor in the area over the head of the pancreas. The underlying etiology is unidentified but is firmly associated with alcohol abuse. We report the case of a 45-year-old male patient with chronic alcohol abuse who was admitted to our hospital with upper abdominal pain radiating to the back and weight loss. Laboratory data were within normal limits, except for the level of carbohydrate antigen (CA) 19-9. An abdominal ultrasound and computed tomography (CT) scan revealed swelling of the pancreatic head and duodenal wall thickening with luminal narrowing. We performed an endoscopic ultrasound (EUS) with fine needle aspiration (FNA) from the markedly thickened duodenal wall and the groove area, which revealed only inflammatory changes. The patient improved and was discharged. The principal objective in managing GP is to exclude a diagnosis of malignancy, whilst a conservative approach might be more acceptable for patients instead of extensive surgery.

Personalized treatment of patients with complications after nasolacrimal groove contouring

Contouring of the nasolacrimal groove area is becoming an increasingly popular procedure due to the rapid onset of a pronounced aesthetic result, however, in recent years, there has been an increase in the pool of complications both in the early and late post-injection recovery period. Meanwhile, there are no differentiated approaches to the choice of physiotherapy techniques and their combinations depending on the genetic profile of the patient and the clinical and functional picture of the complication. Objective: to develop and evaluate the use of personalized physiotherapy in patients with complications after the injection of fillers based on stabilized hyaluronic acid, taking into account patients’ genetic predisposition. Material and methods. The study analyzed the data of 47 patients, aged 35.7±10.2, with a diagnosis of L57.4 — cutis laxa senilis, who received late complications (local edema, filler contouring, sensitivity change at the filler injection site) after the injection of a filler based on stabilized hyaluronic acid in the nasolacrimal groovearea. All patients underwent genetic testing on the Cosmetology panel before the start of treatment. There were 3 groups that received longidase diadinamophoresis, injection carboxytherapy of the nasolacrimal groove area, or a combination of the above techniques. Result. When using a combined course of longidase diadinamophoresis and injection carboxytherapy, there was a significant decrease in such clinical manifestations as contouring, local edema and neuropathy; the psycho-emotional state of patients stabilized. In addition, the therapeutic complex significantly accelerated the biodegradation of the filler and had a restructuring effect on the skin of the nasolacrimal furrow, reducing the thickness of the dermis, increasing the dermis density coefficient, and accelerating the biodegradation of the superficially injected preparation, compared to other study groups. Conclusion. The personalized combined use of the technique, including a course of longidase diadinamophoresis and injection carboxytherapy for the correction of complications of nasolacrimal groove contouring with fillers based on stabilized hyaluronic acid in the form of local edema, neuropathy, and filler contouring, is a highly effective treatment method, which is confirmed by the relief of clinical symptoms, acceleration of biodegradation of the drug, and improvement of the quality of life of patients.

Low-cycle fatigue of V-notched cylindrical samples of bronze alloy

The article presents the results of experiments on cyclic loading of samples with an annular V-shaped notch and their mathematical modeling. The tests were carried out on specimens of the BrKh08-Sh alloy with a cyclic change in the tensile load from 0 to a given value. Under such loading, the material in the groove area is subjected to cyclic elastoplastic deformation, which leads to failure due to low-cycle fatigue. When testing samples using the digital image correlation method, the deformation of the material on the surface of the undercut was measured, which made it possible to determine the nature of the change in its range from cycle to cycle. Mathematical modeling of experiments is carried out according to the finite element method. For this purpose, models of elastic-plastic deformation and accumulation of material damages are introduced into the SIMULIA Abaqus software package. The plasticity model is based on the theory of flow under combined hardening. The damage accumulation model is based on the energy strength criterion. The article presents the basic equations used to calculate the models. The material parameters are determined and verified based on the results of a basic experiment on cyclic tension-compression of a smooth cylindrical sample under asymmetric rigid loading. Based on the results of the calculation, cartograms of stresses, deformations, and accumulated damages were constructed. It is shown that when the sample is unloaded, in the area of stress concentration close to the annular groove, compressive stresses arise, the values of which are close to the values of tensile stresses at the moment of application of the maximum load. The results of mathematical modeling are compared with the experiment. A comparison of the results was carried out in terms of the range of axial deformation of the material on the surface of the undercut and the number of cycles before failure.

Design of Structure Parameters of Sliding Vane Pump Based on Lifting Characteristics

Abstract Limited by the harsh downhole working environment and its structural feature, the sliding vane pump (SVP), which is an all-metal artificial lift method considered to be widely used in thermal recovery well and high gas/oil ratio well, has not been widely applied as expected. To further improve the efficiency of SVP, this study explores how to optimize the structure parameters and the usage of the pump based on its lifting characteristics, in view of the stagnation in the development of SVP. The main results show that (a) optimization of the inlet (outlet) position parameters will bring effective pre-expansion (precompression) of each chamber once it enters the closed state, to avoid ineffective suction and high-pressure backflow. (b) The mathematical model of the pressure difference between the two sides of the vane at any position is derived by means of piecewise function. (c) Increasing the number of vanes can not only increase the mean value of instantaneous displacement but also shorten the discharge period and reduce the flow pulsation. Compared with the adjacent even number of vanes, the odd number of vanes has a more uniform instantaneous displacement. (d) A larger cross-sectional area of the rotor groove can result in a lower volume efficiency at the same gas–liquid ratio, and the effect of rotor groove on volume efficiency is more significant under high gas–liquid ratio conditions.

Establishment and validation of visual assessment for the severity of lacrimal groove wrinkles in Chinese females.

This study was undertaken to establish and validate a new wrinkle clinical assessment scale to measure Chinese Han women`s validated lacrimal groove. Three clinical investigators asked to rate lacrimal groove wrinkles severity one each side for 30 photographic images from 15 subjects. Five-grade rating scale has been used in this clinical assessment. Scale definitions was standardized by 6 researchers in visual and descriptive formats. Assessments were conducted independently and were repeated after 1week. For 30 photos from 15 subjects, test-retest of three investigators analyzed by Spearman's correlation were between 0.967 and 0.993 (p<0.001), and by ICC Cronbach's α were between 0.989 and 0.997 (p<0.001); intraobserver agreement of three investigators analyzed by Spearman's correlation were between 0.652 and 0.897 (p<0.001), and by ICC Cronbach's α were between 0.840 and 0.959 (p<0.001). This lacrimal groove wrinkles visual assessment scale is a valid and reliable instrument for quantitative assessment of China woman skin folds with inter- and intraobserver consistency. This assessment scale should prove a useful clinical tool by allowing objective and reproducible grading for assessing the effectiveness of lacrimal groove area.

Stab access fascia suspension lift: A facelift technique without skin excision and visible scar.

Traditional middle and lower facelifts are not suitable for patients with mild skin laxity or who wish to avoid incision scars. We present the stab access fascia suspension lift (SAFS-lift) technique, which does not require regular skin incisions, as a reliable surgical facelift strategy for the lower and middle face. From September 2020 to September 2021, 38 patients underwent SAFS-lift. SAFS-lift involved (1) incomplete subcutaneous undermining with hydrodissection-assisted tunneling; (2) complete subcutaneous undermining with a dissecting cannula in the zygomatic buccal groove area and hollow below zygomatic arch; and (3) maximal firm superficial musculoaponeurotic system suspension with polydioxanone barbed threads in loops. All patients evaluated the outcome according to the Global Aesthetic Improvement Scale. Four plastic surgeons evaluated postsurgery result with a five-point Likert scale (5=excellent, 4=good, 3=fair, 2=no change, and 1=worse). Thirty-six patients were successfully enrolled. The mean follow-up period was 14.72 ± 3.89 months. No patients showed visible scarring 6months after surgery. The minor complication rate was 19.4%. They all subsided within 1-6 weeks without treatment. No infection, hematoma, seroma, or facial nerve injury was observed. Patients' outcome ratings were 4.22 ± 0.58 (3months), 4.69 ± 0.46 (6months), and 4.69 ± 0.54 (1year). Surgeons' outcome scoring was 3.98 ± 0.95. Stab access fascia suspension-lift is a predictable, effective, and safe facelift technique that can be performed without making noticeable incisions and resecting the skin.