Standard Strip Research Articles

Development and research of the cultivator frame design made of non-standard beams

The paper presents the results of the development and study of the strength of the cultivator frame made of non-standard beams. The term “non-standard beam” refers to a off-sized beam welded from steel strips. As such stripes, both standard hot-rolled strips and strips cut from standard cold-rolled or hot-rolled sheets can be used. The main advantage of the proposed frame design is the relatively low cost and availability of materials for its manufacture, as well as the potential to minimize the weight of the finished product by changing the thickness and dimensions of the strips used. Frame design and calculations were performed by the Autodesk Inventor Professional environment.

THE IMPACT OF FOREST BELTS ON THE ECOLOGICAL CONDITIONS OF AUTOMOBILE TRANSPORT LAND

Environmental pollution by road emissions, including nitrogen oxide, dioxide, lead, was investigated. It was established that roadside green spaces, which are a natural barrier and delay the spread of pollution to the roadside, play an important protective role in the roadside. It was determined that the most common plantating along autotomobile roads are protective forest plantating. These plantings include natural forests and forest plantatings of linear type, which are located in the standardized strips of land along the roads or which are intended for their creation. These forest areas make protective functions and minimize the occurrence of negative impacts to the surrounding areas. Lately intensive construction works are being carried out, the fleet of trucks and cars, public automobile transport is increasing, the requirements for the construction of atomobile roads in accordance with the current environmental norms were substantiated, the necessity for inventory of forest plantations along the roads was substantiated. That is why the situation requires continuous updating of forest belts along the automobile roads. It is found that the most informative methods for the inventory of forest belts are space pictures with ultra-high spatial resolution of about one meter (type ICONOS). The stages and the works` list during the inventory of roadside forest belts were determined. The proposals for forecasting the required number of protective forest belts area in the future were substantiated. The basic State building codes and environmental standards, which are guided during the design and construction of automobile roads, were analyzed.

Treatment of corneal endothelial damage in a rabbit model with a bioengineered graft using human decellularized corneal lamina and cultured human corneal endothelium.

We aimed to investigate the functionality of human decellularized stromal laminas seeded with cultured human corneal endothelial cells as a tissue engineered endothelial graft (TEEK) construct to perform endothelial keratoplasty in an animal model of corneal endothelial damage. Engineered corneal endothelial grafts were constructed by seeding cultured human corneal endothelial cell (hCEC) suspensions onto decellularized human corneal stromal laminas with various coatings. The functionality and survival of these grafts with cultured hCECs was examined in a rabbit model of corneal endothelial damage after central descemetorhexis. Rabbits received laminas with and without hCECs (TEEK and control group, respectively). hCEC seeding over fibronectin-coated laminas provided an optimal and consistent endothelial cell count density and polygonal shape on the decellularized laminas, showing active pump fuction. Surgery was performed uneventfully as standard Descemet stripping automated endothelial keratoplasty (DSAEK). Corneal transparency gradually recovered in the TEEK group, whereas haze and edema persisted for up to 4 weeks in the controls. Histologic examination showed endothelial cells of human origin covering the posterior surface of the graft in the TEEK group. Grafting of decellularized stroma carriers re-surfaced with human corneal endothelial cells ex vivo can be a readily translatable method to improve visual quality in corneal endothelial diseases.

Structured and graphitized boron doped diamond electrodes: Impact on electrochemical detection of Cd2+ and Pb2+ ions

Here we introduce the structuring of boron doped diamond (BDD) electrodes using a self-organised mask and reactive ion etching (RIE) in oxygen plasma for electrochemical measurements of selected metal ions. The samples were analysed by SEM, Raman and X-ray photoelectron spectroscopy. The electrochemical performance of structured BDD was compared to as-grown BDD and standard glassy carbon (GC) electrodes employing standard cyclic voltammetry and differential pulse anodic stripping voltammetry. Separate and simultaneous detection of Cd2+ and Pb2+ ions is discussed in relation to the electrode morphology and content of graphitic phase. To determine trace amounts of metal ions we evaluated the repeatability of measurements, which is statistically expressed as the relative standard deviation (RSD) of consecutive determinations. Based on RSD data, the most suitable candidate for the separate detection of Cd2+ and Pb2+ ions was found the structured BDD electrode consisting of nanotips and small nanorods, respectively. Two times better RSD was found for the structured BDD than for the as-grown BDD electrode. Electrochemical measurements provided in the complex mixture consisting both of Cd2+ and Pb2+ ions revealed the small BDD nanorods as the most suitable surface morphology to separate recognition of Cd2+ and Pb2+ ions.

Effect of a moving automated shot peening and peening parameters on surface integrity of Low carbon steel

Abstract Shot peening is a widely utilized process in industry. It helps to increase fatigue and stress corrosion resistance by creating beneficial compressive residual surface stresses of materials. Whilst very good results are achieved with this process, there is always an increasing demand by industry and material researchers for improved material surface quality, system reliability, and consistency controls of the process. First main objective of this work was to study the effect of an automated moving shot peening process on the surface integrity of low carbon steel material. Second objective was to discuss and present peening saturation and intensity results and model in a new approach in terms of peening speeds along side the traditional procedure which shows peening saturation and intensity results in terms of peening times. Third objective of this study was to examine the effects of: process air pressure, nozzle stand-off distance, nozzle speed, and peening angle on coverage, saturation, and surface quality utilizing the moving shot peening. This study showed that 276 kPa air pressure, 203 mm stand-off distance, and 5.3 mm/sec nozzle speed are the optimum conditions for the shot peening process parameters examined on standard Almen strips samples which resulted in minimize surface irregularities, maximize compressed layer thickness and uniformity, and minimize process time.

Efficacy of the Fluorescein Tear Breakup Time Test in Dry Eye.

To examine the effects of volume and method on fluorescein tear breakup time (TBUT) values and to evaluate test efficacy in an independent sample free of selection bias. Subjects were assessed using a battery of dry eye tests (DETs). Efficacy study: Subjects were randomized to the DET, standard strip, and liquid NaFl on separate days. A masked examiner measured TBUTs from video recordings. Verification study: Subjects were investigated for efficacy using volumes of 5.0 and 2.0 μL mL of NaFl for TBUT. Efficacy study: 46 subjects completed the study. Log-transformed TBUTs were significantly different, normal subjects versus dry subjects, for all 3 methods (all P values < 0.001). Area under the curves (AUCs), cut-points, sensitivity, and specificity were 1) DET: 0.873, 4.4 seconds, 0.97, and 0.67, respectively; 2) 2.0 mL: 0.901, 3.22 seconds, 0.90, and 0.87, respectively; and 3) standard strip: 0.912, 3.42 seconds, 0.97, and 0.80, respectively. Verification study: Data splitting analysis for the 2.0 μL data (n = 174 dry subjects and 97 normal subjects) generated an AUC of 0.917 and a cut-point of 6.05 seconds for a sensitivity of 0.87 and a specificity of 0.81. The 5.0 μL sample yielded an AUC of 0.940, with a sensitivity and specificity of 0.92 and 0.83, respectively, at a cut-point of 5.5 seconds. Little difference in TBUT was found using the 3 clinical methods with video recordings. Analysis using liquid NaFl suggests that the TBUT test has excellent diagnostic accuracy and that a cut-point of 5.3 to 6.0 seconds is the optimum to differentiate normals from persons with dry eye.

Comparative gonad histology and semen quality of normal (XY) and neo‐males (XX) of Atlantic salmon (Salmo salar)

With an overarching objective of improving the hatchery production of Atlantic salmon (Salmo salar) all-female progeny, this study comparatively evaluated the reproductive parameters between normal (genotype XY) and neo-males (genotype XX). Four normal (XY) and seven neo- (XX) males, from the same brood stock, distinguished by their ability to or lack of expressing semen, respectively, were comparatively evaluated. The left testicular lobe was used for histomorphometric analyses, while the right for semen collection and sperm quality analyses. Histomorphometric observations revealed that neo-male testes are irregularly shaped, and have poorly formed seminiferous ducts, higher proportions of interstitial tissue and lower gonadosomatic index (p < .05). In addition, hypertrophied and cyst forming Sertoli cells were found in these individuals which collectively appear to form a physical barrier, precluding the semen collection by standard stripping techniques and reducing sperm quality. Particularly, semen motility (80.69 ± 2.4% and 57.2 ± 36.5% for XY and XX respectively) and duration of motility (99.31 ± 28.03 s and 66.84 ± 23.83 s for XY and XX respectively) of neo-males were most compromised (p < .05). Interestingly, the TUNEL assay indicated no signs of apoptotic tissue suggesting that the histological differences may relate to delayed physiological/sexual maturity of neo-males.

Recurrence Rate after “One-Step” CO2 Fiber Laser Vaporization versus Cystectomy for Ovarian Endometrioma: A 3-Year Follow-up Study

Study ObjectiveTo assess postoperative recurrence rates in patients with endometriomas managed by either “one-step” CO2 fiber laser vaporization or cystectomy. DesignRetrospective study with prospective recording of data. SettingUniversity hospital. PatientsOne hundred twenty-five patients with symptomatic endometriomas. InterventionsPatients underwent a standardized laparoscopic stripping technique (group 1) or cyst vaporization with CO2 fiber laser (group 2). After surgery, patients were incorporated in a prolonged surveillance program with periodic clinical follow-up to check for recurrence of the cyst and/or recurrence of symptoms. Endometrioma recurrence was defined as an ovarian cyst (>10 mm) with a typical aspect arising on the operated ovary identified by transvaginal ultrasound. Measurements and Main ResultsThe primary endpoint was the comparison of recurrence rates between the 2 groups. The secondary endpoint was the evaluation of endometriosis-related pain recurrence in the 2 groups. Other endpoints selected for analysis included the identification of risk factors for the recurrence of endometrioma and of endometriosis-related symptoms. The mean follow-up was 29 ± 13 months (range, 13–49). Recurrence of ovarian endometriosis was recorded in 6.3% of patients (n = 4) treated with cystectomy and in 4.9% of patients (n = 3) managed with CO2 fiber laser (p = .74). Recurrence of endometriosis-related pain was observed in 5 patients (7.8%) in group 1 and in 6 patients (9.8%) in group 2 (p = .67). Mean endometrioma diameter > 5 cm at the time of surgery was identified as the only independent poor prognostic indicator for cyst recurrence (p = .008; odds ratio [OR], 2.21; 95% confidence interval [CI], 1.19–3.32). Moreover, the presence of deep endometriosis at surgery (p = .032; OR, 4.60; 95% CI, 1.14–18.57) and discontinuation of hormonal treatment (p = .015; OR, 3.18; 95% CI, 1.25–8.06) were independent poor prognostic indicators for pain recurrence. ConclusionThis study suggests that one-step CO2 fiber laser vaporization may be effective for endometrioma treatment because it is associated with recurrence rates comparable with those occurring after cystectomy, with the advantage of being an ovarian tissue-sparing technique.

The tear VEGF and IGFBP3 in healthy and diabetic retinopathy

Diabetic retinopathy is an important problem worldwide. The purposes of this study were to measure and analyze VEGF and IGFBP3 level changes in tears of type 2 diabetics with and without retinopathy. In a case–control study, tear samples of 30 diabetes patients without diabetic retinopathy (DNR) were collected, as well as tears of 30 patients with diabetes retinopathy (DR), and 30 healthy subjects without diabetes as the control group by Schirmer’s standard strip, who were matched in terms of age and sex with the other groups. VEGF and IGFBP3 concentration was measured by ELISA method. HbA1c, VEGF, and IGFBP3 were measured in all 3 groups and statistically analyzed. The percentage of HbA1C in the DNR group was clearly higher than the control group. Also, there was a significant difference in the percentage of HbA1C between DR and DNR groups. The concentration of VEGF in tears statistically increased in comparison with control (P < 0.05) but the IGFBP3 level did not change. The VEGF level in tears is clearly linked with the process of DR; however, there wasn’t any significant relationship between the level of IGFBP3 in tears and diabetic retinopathy. It is concluded that VEGF can be used as a noninvasive method for the diagnosis of diabetic retinopathy.

Effect of Sorghum-tigernut Ibyer (A Traditional Gruel) on the Fasting Blood Glucose Levels of Alloxan-induced Diabetic Rats

Background: There is growing interest in the use of natural foods in the management of chronic diseases like diabetes. Ibyer is a fibre rich gruel consumed amongst the Tiv people of Benue State made from whole sorghum or millet flours.&#x0D; Aim: The aim of the study was to evaluate the effect of sorghum-tigernut ibyer on the fasting blood glucose levels and body weight of alloxan monohydrate-induced diabetic rats.&#x0D; Methods: Sorghum flour (SF) and tigernut flour (TNF) were blended at different proportions (100:00; 90:10; 80:20; 70:30) for the purpose of ibyer production. The flour samples were subjected to proximate analysis using standard analytical procedures, the sensory attributes of ibyer produced from the different flour samples was evaluated on a 9-point hedonic scale. Thirty (30) male Wistar rats (100–180 g body weight) were grouped into five (1-5) each group containing six rats. They were induced with diabetes by injecting them with 150ml/kg of body weight with alloxan monohydrate dissolved in saline water (0.9% NaCl) except for group 1. Blood samples were collected from the tail of the rats, prior to induction, 48hrs after induction and 72 hrs after three days of continuous feeding with test diet. Fasting blood glucose was measured using a standard glucometer and test strips.&#x0D; Results: The sensory attributes indicated that ibyer produced from the flour samples were generally acceptable. Fasting blood glucose levels after 72 hrs of feeding were found to be lowered more in groups giving flours with a higher proportion of Tigernut.&#x0D; Conclusion: The results indicated that sorghum-tigernut ibyer exerted hypoglycaemic effect on the experimental animals.

Signal enhancement on gold nanoparticle-based lateral flow tests using cellulose nanofibers

Lateral flow paper-based biosensors merge as powerful tools in point-of-care diagnostics since they are cheap, portable, robust, selective, fast and easy to use. However, the sensitivity of this type of biosensors is not always as high as required, often not permitting a clear quantification. To improve the colorimetric response of standard lateral flow strips (LFs), we have applied a new enhancement strategy that increases the sensitivity of LFs based on the use of cellulose nanofibers (CNF). CNF penetrate inside the pores of LFs nitrocellulose paper, compacting the pore size only in the test line, particularly near the surface of the strip. This modification retains the bioreceptors (antibodies) close to the surface of the strips, and thus further increasing the density of selectively attached gold nanoparticles (AuNPs) in the top part of the membrane, in the test line area, only when the sample is positive. This effect boosts in average a 36.6% the sensitivity of the LFs. The optical measurements of the LFs were carried out with a mobile phone camera whose imaging resolution was improved by attaching microscopic lens on the camera objective. The characterization of CNF into paper and their effect was analyzed using atomic force microscope (AFM) and scanning electron microscope (SEM) imaging techniques.

Specific aspects of the radiographic morphometric and densitometric characteristics of mandible of the rats with experimental diabetes mellitus after tooth extraction

Diabetes mellitus is regarded today as a metabolic disease, which is considered to be a modulator of endodontic infections, is responsible for altering the immune and inflammatory responses, impedes the healing process, and contributes to damage of organs and tissues of the body, including tooth pulp and periapical tissues. The aim of the work is to study the radiographic characteristics of the dental septum of the alveolar crest of the mandible, crown and root of the low molars of rats with experimental streptozotocin diabetes at different times of the post-extraction period (the 1 st , 7 th and 14 th day). Materials and methods. Studies were conducted on 120 male Wistar rats, 8–10 months old, divided into eight groups of 15 animals each. The experimental diabetes mellitus was modelled in 45 animals by a single administration of streptozotocin interperitoneally (SIGMA Chemical, the USA) at a dose of 50 mg/kg, diluted in 0.5 ml of 0.1 M citrate buffer (pH 4.5) ex tempore, on the 21 st day after its induction the level of fasting glucose was determined (by the glucose oxidise method using standard test strips Test Strip II, glucometer Glucocard, Japan), which was 24.7 ± 2.2 mM/l. The extraction of the first low molar of the right mandible was realised using thiopental anaesthesia (40 mg / kg dose) with additional local infiltration anaesthesia with Ubistesine (3M Deutschland GmbH, Germany).On the 1 st , 7 th , and 14 th day, dates that correspond to the experiment after the extraction of the tooth, the rats were decapitated using thiopental anaesthesia (dose 40 mg/kg).The visiography of the mandible was performed using a computerized 3D CBCT tomograph Panoura 18S Panoramic 3D. With the help of digital image analysis the radiographic density of tissues of the alveolar socket of the removed 1 st molar, crown of the 1 st , 2 nd and 3 rd molars, their root and dental septum of the alveolar crest were determined. The results. Radiological density of the interalveolar and interradicular septa between the 1 st –3 rd molar and the 1 st molar root, which is the most traumatized and loaded rats' tooth, is decreased in the rats with experimental diabetes mellitus. Tooth extraction in the rats with diabetes mellitus results in the increase (not in the decrease as it is observed in control group) of radiological density a day after in the alveolar socket and the adjacent 2 nd and 3 rd molars, that may be caused by significant infiltration related to the secondary alteration. The final stage of the local inflammatory reaction resorptive phase that corresponds to the 7 th day of post-extraction period is characterized by almost complete restoration of the alveolar socket radiological density in the control rats, whereas in the rats with diabetes mellitus radiological density of the studied sites decreases and this process continues on the 14 th day. C onclusions. In the work it was found out that the extraction of a tooth in rats with normal carbohydrate metabolism is accompanied by dynamic changes in radiological density not only in the extraction area of the 1 st molar (it decreases on the 1 st day in the area of the root more than 2.7 times and by 65 % in the area of interalveolar and interradicular septa with its restore to the 14 th day), the inflammatory process affects the adjacent 2 nd and 3rd molars, leading to its decrease on the 1 st day in the area of interalveolar and interradicular septa of the 2 nd molar by 24.4 % and 3 rd molar – by 16.8 % with its restore to the 7 th day. It was revealed that the pre-existing early resorptive phase of the local inflammatory reaction ends by the 7 th day of the post-extraction period, changing to the reparative by the 14 th day. The development of experimental diabetes mellitus in rats leads to an increase in resorptive processes in the mandible bone tissue, which is manifested by a decrease in radiological density in the area of the 1 st molar root by 2.27 times along with its increase in the interalveolar and interradicular septa area of all three low molars by 22.0 %, 21.8 % and 18.3 %, respectively. Experimental diabetes contributes to the particular course of the wound process after tooth extraction. At the same time, it is an important pathogenetic link for the formation of complications due to the disturbance of the resorption-reparative relationship in the area of the alveolar socket and the adjacent molars.

Magnetic SERS Strip for Sensitive and Simultaneous Detection of Respiratory Viruses.

Rapid and early diagnosis of respiratory viruses is key to preventing infections from spreading and guiding treatments. Here, we developed a sensitive and quantitative surface-enhanced Raman scattering-based lateral flow immunoassay (SERS-based LFIA) strip for simultaneous detection of influenza A H1N1 virus and human adenovirus (HAdV) by using Fe3O4@Ag nanoparticles as magnetic SERS nanotags. The new type of Fe3O4@Ag magnetic tags, which were conjugated with dual-layer Raman dye molecules and target virus-capture antibodies, performs the following functions: specific recognition and magnetic enrichment of target viruses in the solution and SERS detection of the viruses on the strip. Based on this strategy, the magnetic SERS strip can directly be used for real biological samples without any sample pretreatment steps. The limits of detection for H1N1 and HAdV were 50 and 10 pfu/mL, respectively, which were 2000 times more sensitive than those from the standard colloidal gold strip method. Moreover, the proposed strip is easy to operate, rapid, stable, and can achieve high throughput and is thus a potential tool for early detection of virus infection.

Bacteria Recovered from Cultured Gilt-Head Seabream (Sparus aurata) and their Antimicrobial Susceptibilities

Objective: Gilt-head seabream (Sparus aurata) is an important species for Turkish aquaculture and bacterial diseases are oneof the limiting factors for the production of this species. The aim of this study is the identification of the bacterial disease agents in cultured gilt-head seabream in Turkey and the determination of their antibacterial susceptibilities. Materials and Methods: In this study, 27 diseased gilt-head seabream samples between 3-130 g, showing various clinical symptoms, were examined bacteriologically. Bacterial isolates recovered from moribund fish samples were identified by using standard bacteriological methods and API 20E rapid identification strips. Antibiotic susceptibility tests of 10 different substances against these isolates were determined by using Kirby-Bauer disc diffusion method.Results: Vibrio anguillarum, V. scophthalmi, V. logei, V. harveyi, Pseudomonas anguilliseptica, P. stutzeri, Staphylococcus sp. and Micrococcus luteus isolates were isolated from diseased fish samples as pure and mixed infection. It was detected that API 20E may give erroneous results for fish pathogenic bacteria since they are not included in the database of the kit. Generally, enrofloxacin, florphenicol and oxytetracycline were found to be the most effective antibiotics against bacterial isolates.Conclusion: This study is the first report for V. scophthalmi, V. logei, V. harveyi, P. stutzeri and M. luteus infections of gilt-head seabream in Turkey.

Improved fractal Weyl bounds for hyperbolic manifolds (with an appendix by David Borthwick, Semyon Dyatlov and Tobias Weich)

We give a new fractal Weyl upper bound for resonances of convex co-compact hyperbolic manifolds in terms of the dimension n of the manifold and the dimension \delta of its limit set. More precisely, we show that as R\to\infty , the number of resonances in the box [R,R+1]+i[-\beta,0] is \mathcal O(R^{m(\beta,\delta)+}) , where the exponent m(\beta,\delta)=\mathrm {min}(2\delta+2\beta+1-n,\delta) changes its behavior at \beta={n-1\over 2}-{\delta\over 2} . In the case \delta&lt;{n-1\over 2} , we also give an improved resolvent upper bound in the standard resonance free strip \{\Im\lambda &gt; \delta-{n-1\over 2}\} . Both results use the fractal uncertainty principle point of view recently introduced in [DyZa]. The appendix presents numerical evidence for the Weyl upper bound.

Hybrid electroslag cladding (H-ESC): an innovation in high speed electroslag strip cladding

Application of strip cladding using electroslag welding process to cover large surface areas of vessels for oil and gas industries has been a common weld cladding method in last few decades. There has been continuous development by welding consumable suppliers to improve this method further through introduction of high-speed ESW flux and specially designed over-alloyed welding strips to achieve required weld metal chemistry in single layer for some of the alloys. However, the conventional method had limitations in achieving desired chemistry with single layer for certain alloys—Ni-625 alloy with max. 5% Fe is one among them. A new variant of electroslag cladding technique (Hybrid Electro Slag Cladding or H-ESC) has successfully been developed and introduced in the market, wherein a 3rd dimension has been added to the conventional ESW strip cladding method of using strip and flux in the form of addition of multiple hot metal cored wires into the molten electroslag weld pool. Addition of multiple hot MCW wires with a particular proportion into the molten weld pool by a uniquely designed digital weld control system helps in controlling the dilution level, thereby achieving clean undiluted cladding chemistry coupled with at least 50% higher welding speed and nearly double the weld deposition rate as compared to conventional ESW cladding technique. In this new high-speed single-layer cladding technique using neutral flux, it is possible to achieve Fe content 40% Ni for Ni-825 cladding in single layer. Similarly, this new technique offers unique solution in case of high-speed single-layer austenitic stainless steel cladding, wherein only one standard stainless steel strip type is used along with neutral flux and desired AWS clean weld metal chemistry is easily achieved for SS 308L, SS 316L, SS 347, and SS 317L by using suitably designed MCW wires. Such solution would immensely help fabricators to minimize their working capital and faster delivery of weld consumables in addition to reaching desired 3.0 mm undiluted weld chemistry in high-speed single-layer cladding of 3.5-mm thick.

Investigation of Corrosiveness Biodiesel Blends Using Polypyrrole Chitosan-Cobalt/Ferrite Nanocomposite

Corrosiveness of palm oil biodiesel blends was measured using surface plasmon resonance with polypyrrole chitosan cobalt ferrite nanoparticles sensing layers. Diesel fuel which is relatively corrosive and lower flash point is often mixed with biodiesel of low corrosiveness and higher flash point. Biodiesel blend fuels were prepared from the mixture of normal palm oil biodiesel and diesel fuel where the percentage of the mixture was in the range of 10–90%. The corrosiveness of all the samples was in the class 1a according to the standard copper strip test, but the concentrations of copper and iron ion that were released in biodiesel blend were distinctly different. In this article, the corrosiveness of biodiesel blend was investigated using surface plasmon resonance from the measurement the concentration of copper and iron ions. The corrosiveness of biodiesel blends consistently decreased with increasing the concentration of biodiesel. Moreover, the sensitivity of polypyrrole chitosan /cobalt ferrite and polypyrrole chitosan sensing layer was compared. Consequently, the polypyrrole chitosan cobalt ferrites have sensitivity higher than polypyrrole chitosan sensing layer.

Roughness effect on shock wave boundary layer interaction area in compressor fan blades passage

The main objective of this research is to study experimentally the effect of transition on the flow structure of the shock wave boundary layer interaction in the blades passage of a compressor cascade. For this purpose a model of a turbine compressor passage was designed and assembled in a transonic wind tunnel. In the experiment the distributed roughness with different heights and locations was used to induce transition upstream of the shock wave. Three locations of distributed roughness in form of standard sandpaper strips were chosen to apply on the blade. The average roughness height comprised in a range of 8 to 16 μm. All together 8 different flow cases were investigated. The paper focuses on the influence of the boundary layer transition induced by different roughness values and locations on the flow pattern in the blades passage of a compressor cascade. Very promising results were obtained in the roughness application for the boundary layer transition control, demonstrating a positive effect in changing the nature of the interaction.

Bi-material strip based temperature sensor design and optimization through thermo-mechanical multi-physics modeling

ABSTRACTWith the capability of additive manufacturing, complex structures are easily fabricated to achieve various design purposes. In this work, a bi-material strip temperature sensor with complex periodic pattern design is purposed and investigated through both the analytical modeling and multi-physics finite element analysis. Three design patterns are considered: standard, E-shape and S-shape. In the standard solid strip design, the curvature of the bi-material strip under temperature variation is in a linear relationship with the coefficient of thermal expansion (CTE) difference, but in a reciprocal relationship with the strip thickness. The curvature of the bi-material strip depends on the Young’s modulus ratio and layer thickness ratio of the two materials, but is independent of the magnitude of the materials’ Young’s modulus. Based on analytical derivation and numerical validation, the optimized design parameters can be provided. Compared to S-shape pattern design, E-shape pattern design can significantly increase the temperature sensitivity of the bi-material strip. An analytical prediction of the E-shape pattern’s temperature sensitivity is introduced and discussed. This work proves the concept that new design space becomes available with the capability of additive manufacturing, and provides the general design guideline for a bi-material strip based temperature sensor with possible design patterns.

Assessment of ovarian reserve after cystectomy versus 'one-step' laser vaporization in the treatment of ovarian endometrioma: a small randomized clinical trial.

STUDY QUESTIONDoes CO2 laser vaporization offer better results in treating endometrioma in terms of ovarian reserve preservation compared to traditional cystectomy?SUMMARY ANSWERAssessing both antral follicle count (AFC) and serum anti-Müllerian hormone (AMH) levels as measures of ovarian reserve, the results suggest that CO2 technology may be an alternative treatment for endometrioma, causing minimal damage to adjacent healthy ovarian tissue.WHAT IS KNOWN ALREADYExcisional surgery has been questioned as an ideal surgical approach for endometriomas because it is associated with potential reduction of ovarian reserve. Recently, vaporization with CO2 laser in-line-of-sight, according to the ‘three-step procedure’, has been proposed as the best method to preserve ovarian function. However, no randomized controlled trials have been conducted to compare cystectomy and ‘one-step’ CO2 fiber laser vaporization (without GnRH agonist therapy) with respect to the ovarian reserve.STUDY DESIGN, SIZE, DURATIONA multicentre randomized clinical trial including 60 patients was performed between July 2017 and February 2018. Computerized randomization was conducted to allocate them in a proportion of 1:1 either to Group 1 (laparoscopic stripping: cystectomy) or Group 2 (CO2 laser vaporization). Patients in Group 1 underwent a standardized laparoscopic stripping technique; patients in Group 2 underwent drainage of the cyst content, biopsy and vaporization of the internal wall with a CO2 fiber laser. Patients underwent pelvic ultrasound examination to determine the AFC and blood sampling to determine AMH levels before surgery and at 1- and 3-month follow-up.PARTICIPANTS/MATERIALS, SETTING, METHODSPatients undergoing surgery for symptomatic endometriomas (infertility and/or pelvic pain) larger than 3 cm were randomized in two groups according to the surgical technique. Patients aged ≥40 years, or with deep infiltrating endometriosis/adenomyosis, or previously submitted to surgical procedures on the ovaries or to hysterectomy were excluded from the study. The primary endpoint was the comparison of intra-group AFC changes before and after surgery (ΔAFC) between the two groups (ΔAFC Group 1 versus ΔAFC Group 2). The secondary endpoint was the modification of serum AMH before and after surgery (ΔAMH) between the two groups (ΔAMH Group 1 versus ΔAMH Group 2).MAIN RESULTS AND THE ROLE OF CHANCEThe AFC of the operated ovary was significantly increased in Group 2 (laser vaporization) compared with Group 1 (cystectomy) after surgery (Group 1: from 4.1 ± 2.2 [mean ± SD] at baseline to 6.3 ± 3.5 at 3-month follow-up; 95% CI: 0.9–4; Group 2: from 3.6 ± 1.9 at baseline to 8.6 ± 4.2 at 3-month follow-up; 95% CI: 2.8–7.1; P = 0.016); serum AMH levels were significantly reduced at 3 months in Group 1 (from 2.6 ± 1.4 ng/mL at baseline to 1.8 ± 0.8 ng/mL at 3-month follow-up; 95% CI: −1.3 to −0.2; P = 0.012) compared with no reduction in Group 2 (from 2.3 ± 1.1 ng/mL at baseline to 1.9 ± 0.9 ng/mL at 3-month follow-up; 95% CI: −1 to −0.2; P = 0.09).LIMITATIONS, REASON FOR CAUTIONThe key limitations of the trial were the low accuracy of AFC in estimating the ovarian reserve in ovaries with endometriomas, the limited study size and the relatively short follow-up, which do not allow us to draw definitive conclusions.WIDER IMPLICATIONS OF THE FINDINGSThe present study suggests that CO2 technology may treat endometrioma with minimal damage to the adjacent healthy ovarian tissue; however, this study should be considered as a preliminary clinical trial, intended to stimulate future larger trials to address this clinically relevant issue.STUDY FUNDING/COMPETING INTEREST(S)None.TRIAL REGISTRATION NUMBERClinicalTrials.gov NCT03227640.TRIAL REGISTRATION DATE9 July 2017.DATE OF FIRST PATIENT’S ENROLLMENT24 July 2017.