Simplified Testing of the Bond Strength of Adhesives Used for Bonded Anchors

The analysis presented in this paper is focused on problems of bond strength as an overall bond quality parameter of industrial adhesives for structural anchoring. In the first part, the problem of bond strength as the most important parameter influencing the final anchor resistance to tension load is described. Further in the text, a new methodology of simplified testing of the strength parameters of adhesives is described. Special test specimens made from steel are repeatedly used in this methodology. Additionally, results of these tests on some new recipes for adhesive are presented. Especially, epoxy resins with special fillers, such as carbon fibres, carbon nanotubes or graphene, were tested. The use of these adhesives in temperatures close to zero degrees Celsius was also tested.

Single Nodal Diameter Excitation of Turbine Blades: Experimental and Theoretical Study

Validating simulation results of vibrating turbine blades relies on measurements of realistic or academic cyclic structures on special test rigs. In real operation the blades are excited mainly by aerodynamic forces. For measurements of blade vibration on special test rigs, the excitation should be well known. It is desirable to use excitation spectra that consist of only a few engine order excitations. Especially for nonlinear systems, unwanted excitation orders can possibly lead to nonlinear effects which may interfere with the measurement. To separate different engine orders, an innovative electromagnetic excitation device was developed at the institution to overcome the aforementioned problems. The excitation force spectrum is controlled by a variable air gap over the circumference between device and blade. Any desired engine order excitation can be realized. Additionally, by varying the devices coil current in a harmonic fashion, frequency sweeps at constant speed can be performed. In this paper an extensive study of the excitation force spectrum of the device is conducted. Therefore, theoretical investigations of the expectable spectrum are given under simultaneous variation of air gap geometry and excitation current. These predictions are then validated by experiments featuring a small, academic bladed disk. The vibrations of the blades are measured. The device promises to create well predictable and controllable excitation force spectra which will improve the validation strategy in particular of non-linear simulation tools for the prediction of turbine blade vibrations.

Detecting the Disease before it’s Too Late

Specific trials or examination exists in detecting deadly diseases. Various facilities are provided these days for determining many chronic diseases, like in detecting cancer, tuberculosis, keratin level (dialysis), coronary artery disease, etc. But delaying in diagnosing emergency cases which need very quick action will lead to adverse situations. The process of this early detection of disease starts with a special test and further process depends on the special test result whether it is positive or negative. The sad reality of modern technology in the medical industry is that there is very less availability of vanguard doctors, who can help patients in diagnosing their disease, which can be treated successfully as soon as possible diagnosis has been done. Therefore, Hong Kong University (HKU) scientists discovered “Biomarker” which is being rapidly used by physicians, Neuroscientists and epidemiologists in measuring the intensity of disease provided with the details of its cause and treatment. Biomarkers possess possibilities in making wishes of doctors and scientists into reality, to identify that person who is at high risk of any disease so that doctors can take protective measures in saving that life within time. Nevertheless, according to Global data “Biomarkers” are a useful instrument in examining COVID-19 vaccine and fastening the process of clinical trials, decreasing the development cost and decreasing patient security risk. They also can be utilized to find the drug which can help in treating Covid-19 patients and can also be used to determine which drugs might be able to treat COVID-19 patients.

Diagnosis of machine vision of an unmanned vehicle

There is an increase in the number of cars using artificial intelligence. Therefore, it is necessary to provide quality maintenance of artificial intelligence components, such as machine vision (MV). The paper considers a general approach to the diagnosis of the unmanned vehicle. Based on the analysis of the use of existing systems, general requirements for the diagnosis of unmanned vehicle MV were formulated, diagnostic parameters were proposed. To solve the problem of testing, debugging and diagnostics of the MV, it is proposed to use virtual polygons built using the methods of procedural computer graphics. After diagnosing the MV video cameras, if necessary, they are calibrated according to the images of a special test object.

About Identification of Instrument Error Parameters for a Gravity Gradiometer

The article presents the description of two algorithms used for processing of the raw data of a gravity gradiometer. These algorithms are intended for estimation of some instrument errors. The first algorithm is applicable for the instrument operation in its stationary mode, the second proposes the use of a special test bench. Rotary gravity gradiometer of the accelerometric type was taken as a prototype for relevant mathematical models. Nowadays this type of gradiometer is brought to the stage of practical implementation and serial production.

Mathematical Modelling of the Volumetric Efficiency for Fluted Rolls Metering Different Crop Seeds

The objective of this study was to develop a mathematical model for predicting the volumetric efficiency for fluted rolls metering different crop seeds. A special test stand was designed and manufactured in order to conduct experiments in order to find out the volumetric efficiency of the fluted rolls. In order to meet the above objective, alfalfa, barley, coriander, flax, oat, rye, safflower, sesame and wheat seeds were used. Experiments were conducted at different roll revolutions and roll lengths by considering the seed rate for each crop and the rolls were driven by a step motor as controlled by a software installed on a laptop computer. Five replications were achieved for each experiment and a total of 1660 flow rate data was obtained. Five different models for volumetric efficiency were developed. Analysis based on different goodness of fit criteria were achieved to compare models in to order to select the appropriate one. The study conducted not only resulted in developing volumetric efficiency models but also revealed an important finding based on low flow evenness (low CV, %) values obtained as compared to other studies in the literature.

Single Nodal Diameter Excitation of Turbine Blades: Experimental and Theoretical Study

Validating simulation results of vibrating turbine blades relies on measurements of realistic or academic cyclic structures on special test rigs. In real operation the blades are excited mainly by aerodynamic forces. For measurements of blade vibration on special test rigs, the excitation should be well known. It is desirable to use excitation spectra that consist of only a few engine order excitations. Especially for nonlinear systems, unwanted excitation orders can possibly lead to nonlinear effects which may interfere with the measurement. To separate different engine orders, an innovative electromagnetic excitation device was developed at the institution to overcome the aforementioned problems. The excitation force spectrum is controlled by a variable air gap over the circumference between device and blade. Any desired engine order excitation can be realized. Additionally, by varying the devices coil current in a harmonic fashion, frequency sweeps at constant speed can be performed. In this paper an extensive study of the excitation force spectrum of the device is conducted. Therefore, theoretical investigations of the expectable spectrum are given under simultaneous variation of air gap geometry and excitation current. These predictions are then validated by experiments featuring a small, academic bladed disk. The vibrations of the blades are measured. The device promises to create well predictable and controllable excitation force spectra which will improve the validation strategy in particular of non-linear simulation tools for the prediction of turbine blade vibrations.

Evidence-Based Physical Examination for the Diagnosis of Subscapularis Tears: A Systematic Review

Context: There is a renewed interest in diagnosing and treating subscapularis tears, but there is a paucity of clinical guidance to optimize diagnostic decision-making. Objective: To perform a literature review to evaluate advanced maneuvers and special tests in the diagnosis of subscapularis tears and create a diagnostic algorithm for subscapularis pathology. Data Sources: PubMed, MEDLINE, Ovid, and Cochrane Reviews databases. Study Selection: Inclusion criteria consisted of level 1 and 2 studies published in peer-reviewed scientific journals that focused on physical examination. Study Design: Systematic review. Level of Evidence: Level 2. Data Extraction: Individual test characteristics (bear hug, belly press, lift-off, Napoleon, and internal rotation lag sign) were combined in series and in parallel to maximize clinical sensitivity and specificity for any special test evaluated in at least 2 studies. A secondary analysis utilized subjective pretest probabilities to create a clinical decision tree algorithm and provide posttest probabilities. Results: A total of 3174 studies were identified, and 5 studies met inclusion criteria. The special test combination of the bear hug and belly press demonstrated the highest positive likelihood ratio (18.29). Overall, 3 special test combinations in series demonstrated a significant impact on posttest probabilities. With parallel testing, the combination of bear hug and belly press had the highest sensitivity (84%) and lowest calculated negative likelihood ratio (0.21). Conclusion: The combined application of the bear hug and belly press physical examination maneuvers is an optimal combination for evaluating subscapularis pathology. Positive findings using this test combination in series with a likely pretest probability yield a 96% posttest probability; whereas, negative findings tested in parallel with an unlikely pretest probability yield a 12% posttest probability.