Verification of the Thermal Expansion Effect of Silicone Molds Intended for Production of the Prototype Components using Vacuum Casting Technology

The article deals with vacuum casting technology and especially with the assessment of the influence of the tempering temperature of silicone molds on the dimensions of future castings. The aim was to evaluate the actual size of the castings, using different tempering temperatures of the molds and different casting materials. After examining the resulting dimensions of the individual castings, a procedure was established by which these effects could be minimized. In the end, a test of the proposed procedure is performed, which confirmed its correctness.

Structural Timber Connections with Dowel-Type Fasteners and Nut-Washer Fixings: Mechanical Characterization and Contribution to the Rope Effect

Dowel-type fasteners are one of the most used type of connections in timber joints. Its design follows the equations included in the Eurocode 5. The problem with these equations is that they do not adequately contemplate the resistive capacity increase of these joints, when using configurations which provoke the so-called rope effect. This effect appears when using threaded surface dowels instead of flat surface dowels, expansion kits or nut-washer fixings at the end of the dowel. The standards consider this increase through a constant value, which is a poor approximation, because it is clearly variable, depending on the joint displacement and because is much bigger, especially when using nut-washer fixings. It is also very important because of the rope effect trigger interesting mechanisms that avoids fragile failures without warning of the joints. For these reasons, it is essential to know how these configurations work, how they help the joint to resist the external loads and how much is the increase resistance capacity in relationship with the joint displacement. The methods used to address these issues consisted of a campaign of experimental tests using actual size specimens with flat surface dowels, threaded surface dowels and dowels with washer-nut fixings at their ends. The resistance capacity results obtained in all the cases has been compared with the values that will come using the equations in the standards. After the tests the specimens were cut to analyze the timber crushings, their widths, the positions and level of plasticizations suffer in the steel dowels and in the washer-nut fixings and the angle formed in the dowel plastic hinges. With all this information the failure mode suffered by the joints has been identified and compared with the ones that the standards predict. The results for the size materials and types of joints studied shows that the crush width average values go from 20 mm with flat surface dowels, to 24 mm in threaded to 32 mm in threaded with washer-nut fixings. The rope effect force/displacement goes from 100 N/m in threaded surface dowels to 500 N/m in threaded with washer-nut fixings. Finally, the load capacities are on average 290% higher those indicated in the standard. The main conclusion is that the rope effect force should be considered in the standards in more detail as a function of multiple variables, especially the displacement of the joint.

Demographic future of Russia in the UN forecasts: "scientific foresight" and reality

The article provides a brief history of the emergence of demographic forecasts, shows their use by the United Nations, the range of countries for which forecasts were made and are being drawn up, considers demographic forecasts that were carried out during the Soviet era and provides a detailed analysis of demographic forecasts for Russia. In contrast to the forecasts of the population of the Soviet Union as a whole, for Russia they initially began to focus on the downward dynamics. It is concluded that over two decades (1996-2015) in countries with a predominance of the Slavic ethnos (excluding the former republics of Yugoslavia), the population as a whole has decreased to 95.5%, while in countries with a predominance of the Anglo-Saxon ethnos — it increased to 123.8%. The forecasts given in the article are compared with the actual size of the population that has already taken place. Everywhere in countries with a predominance of the Slavic ethnos, the actual population is higher than the predicted, and in countries with a predominance of the Anglo-Saxon ethnos, on the contrary. Comparing the forecasts with the actual population dynamics, the conclusion is substantiated about a noticeable change in the ratio between the two groups of countries united by ethnicity, a decrease in the demographic potential of the Slavic group and its increase in the group with a predominance of the Anglo-Saxon ethnos. In the final part of the work, it is said that the presented rates of change in the population size in 35 years and then in another 50 years, arising from the UN demographic forecasts for 2050 and 2100, as well as the demographic dynamics in the 90s of the twentieth century and in the first 15 years of the new century, indicate that if Russia, like other Slavic countries do not make radical efforts and, accordingly, do not consistently take effective measures to change the demographic trends, then the same thing can happen to Russia as has happened in different centuries to many countries such as Assyria, the Hunnic Empire, etc. The current geopolitical situation in which Russia is, its status as a great power, the country's largest territory in the world, favorable geographical position and colossal natural resources, dictate the need to increase its economic, defense and, naturally, demographic potential.

A Comparison of the Accuracy of WATCHMAN and WATCHMAN FLX Device Sizing between CT, TEE, and Patient Specific 3D Models

Background and Hypothesis: In patients with Atrial fibrillation (AF), the Left Atrial Appendage (LAA) is the most common site of thrombus formation. The LAA occlusion procedure using the WATCHMAN device implant is an alternative for stroke prevention in AF patients. Transesophageal echocardiogram (TEE) and Computed tomography (CT) scans aid in measuring the LAA to predict implant device sizes. However, due to varying LAA anatomy and limited spatial resolution, the current imaging techniques often predict one of two sized devices. The objective of this retrospective study is to compare the accuracy of measurements made preoperatively of the LAA with those on 3D models to determine if they can be used in preoperative planning. We hypothesize 3D models will be more accurate in predicting device size and any anatomical impediments than traditional TEE planning. Project Methods: There were 21 subjects selected who underwent the WATCHMAN FLX procedure at Parkview Heart Institute in 2021. 3D models of LAA were created from CT scans using a Form 2 3D printer. The device sizes predicted for the procedure were determined from Boston Scientific FLX guidelines based on the maximum LAA orifice diameter from TEE, CT, and 3D models. Results: Two-proportion z-test between the 3D model predicted sizes to the actual size deployed demonstrated no statistical significance (p=0.298) demonstrating no difference between 3D model predicted sizes and actual size deployed. Two-proportion z-test between TEE vs actual size and CT vs actual size demonstrated statistical significance, suggesting a difference between the group's predictions. 3D models predicted the accurate device size for 20/21(95%) subjects. TEE measurements of maximum orifice diameter were, on average, lower compared to CT and 3D model measurements. Conclusion and Potential Impact: 3D printed models provide the most accurate device size predictions and can be used to optimize presurgical planning while reducing intraoperative complications.

Fluorescence diagnostics and photodynamic therapy of squamous cell carcinoma of the lateral surface of the tongue using the photosensitizer chlorin e6 by spectroscopic video fluorescence methods

This paper presents the results of using intraoperative fluorescence diagnostics (FD) with the endoscopic video system to increase the efficiency of photodynamic therapy (PDT). The molecular form of chlorin e6 was used as a photosensitizer (PS). All patients received an intravenous administration drug based on chlorin e6 at the concentration of 1 mg/kg. Diagnostics and therapy were carried out in 4 patients diagnosed by malignant neoplasms of the lateral surface of the tongue. Determination of the boundaries by changing the signal of the fluorescence intensity of the tumor was carried out before PDT and after PDT. The efficiency of PDT was assessed by the fluorescent signal of the tumor decreasing when compared with non-pathological normal tissue. The FD method allows to determine accurately the actual size of the tumor and its borders. All patients underwent PDT influenced by the therapeutic laser with a generation wavelength of 660 nm. It is shown that the using of fluorescence diagnostics improves the quality of the photodynamic therapy, since it is possible to assess the photobleaching of the drug during the operation.

Image-based lime size grading using the comparison ratio of the pixel radius and the actual size of lime fruit

Lime is a commercially important fruit in Thailand whose sale price depends on the fruit’s size; hence, farmers must grade limes by size before distribution. However, as lime grading machines are very expensive and each province has different size grading limits, grading is often performed manually, which is time-consuming and error-prone. Agricultural production systems for automatic selection and grading use image processing techniques for extracting key features. Therefore, this study proposes techniques to extract features of limes and to develop analytical methods for grading them. This method can reduce time and cost, and increase accuracy and flexibility for selecting different lime sizes according to each province’s size criteria. To verify our method, we classified limes according to criteria from four Thailand provinces as sample data in an experiment. The focal image feature was the radius or diameter of the lime and the grading conditions were defined by the maximum comparison ratio of the fruit’s radius in pixels to the measured radius of the actual lime in centimeters. The average grading accuracy was 99.59%, which outperformed that of mechanical grading. The processing time was 1.70 seconds per individual fruit.

The Detection of Thread Roll’s Margin Based on Computer Vision

The automatic detection of the thread roll’s margin is one of the kernel problems in the textile field. As the traditional detection method based on the thread’s tension has the disadvantages of high cost and low reliability, this paper proposes a technology that installs a camera on a mobile robot and uses computer vision to detect the thread roll‘s margin. Before starting, we define a thread roll‘s margin as follows: The difference between the thread roll‘s radius and the bobbin’s radius. Firstly, we capture images of the thread roll‘s end surface. Secondly, we obtain the bobbin’s image coordinates by calculating the image’s convolutions with a Circle Gradient Operator. Thirdly, we fit the thread roll and bobbin’s contours into ellipses, and then delete false detections according to the bobbin’s image coordinates. Finally, we restore every sub-image of the thread roll by a perspective transformation method, and establish the conversion relationship between the actual size and pixel size. The difference value of the two concentric circles’ radii is the thread roll’s margin. However, there are false detections and these errors may be more than 19.4 mm when the margin is small. In order to improve the precision and delete false detections, we use deep learning to detect thread roll and bobbin’s radii and then can calculate the thread roll’s margin. After that, we fuse the two results. However, the deep learning method also has some false detections. As such, in order to eliminate the false detections completely, we estimate the thread roll‘s margin according to thread consumption speed. Lastly, we use a Kalman Filter to fuse the measured value and estimated value; the average error is less than 5.7 mm.

Restoration of Dimensions for Ancient Drawing Recognition

This study aims to investigate and determine the actual size of the “cheok” scale—the traditional weights and measures of Korea—to aid in data construction on the recognition of ancient drawings in the field of artificial intelligence. The cheok scale can be divided into Yeongjocheok, Jucheok, Pobaekcheok, and Joryegicheok. This study calculated the actual dimensions used in the drawings of Tonga and Eonjo contained in Jaseungcha Dohae by Gyunam Ha BaeckWon, which helped us analyze the scale used in the southern region of Korea in the 1800s. The scales of 1/15 cheok and 1/10 cheok were used in the Tonga and Eonjo sections in Jaseungcha Dohae, and the actual dimensions in the drawing were converted to the scale used at the time. Owing to the conversion, the dimensions in the drawings of Tonga were converted to 30.658 cm per cheok, and ~31.84 cm per cheok for Eonjo. In this manner, the actual dimensions used in the southern region of Korea around the year 1800 were restored. Through this study, the reference values for drawing recognition of machinery drawings in Korea around 1800 were derived.

Fruit maturity and location identification of beef tomato using R-CNN and binocular imaging technology

The objective of this study was to identify the maturity and position of tomatoes in greenhouse. Three parts have been included in this study: building the model of image capturing and object detection, position identification of mature fruits and prediction of the size of the mature fruits. For the first part, image capturing in different time and object detection will be conducted in the greenhouse for identification of mature fruits. For the second part, the relative 3D position of the mature fruits calculated by the binocular vision was compared with the actual measured position. For the third part, the size of the bounding box from the object detection was compared with the actual size of the mature fruit, and the correlation was calculated in order to pre-adjust the width of the gripper for plucking operation in the future. The precision and the recall of the mature fruits of this study are over 95%. The average error of the 3D position is 0.5 cm. The actual size of the fruits and the R-squared of the size of the bounding box are over 0.9.

SOCIAL MEDIA MARKETING: PROSPECTS AND OPPORTUNITIES FOR SMALL AND MEDIUM ENTERPRISES

This paper aims to explore prospects and opportunities of the use of Social Media Marketing tools by Small & Medium Enterprises (SMEs) in Pakistan, to develop and promote their business. The research data findings postulate the fact that the SMEs constitute over 90 percent of 3.2 million business enterprises listed under the Economic Census of Pakistan (2005,) generate 25 percent of manufacturing export earnings and contribute 30 percent to the annual GDP in the country. Despite this fact, the SMEs are considered to be less formally organized sector of the economy relative to large enterprises, have limited access to financial resources and are limited to their scale of production. Social Media Marketing, on the other hand, operates on a less complex organizational structure, requires lower financial investments and even makes an organization appear to be larger than its actual size. These analogous attributes establish a correlation between SMEs and Social Media Marketing. This paper intends to identify the various possibilities which can contribute to the growth and development of the SME sector in Pakistan. The study examines the data evidence and empirically tests the correlation between SME business progress & social media as a mode of business promotion. Consequently, this research paper focuses on how small businesses can use Social Media not only for advertising and marketing their products and services but also for building the business overall, employing transactional mechanisms, sharing information with customers and receiving their feedback and recommendations on a regular basis.