scholarly journals Development and experimental testing of the technique of ultrasonic control of brazed joints of heat exchangers

2021 ◽  
Vol 2127 (1) ◽  
pp. 012054
Author(s):  
A S Kostyukhin ◽  
E A Pavlukhin ◽  
V V Malyy
Keyword(s):  
Heat Exchangers ◽  
Experimental Testing ◽  
High Reliability ◽  
Scanning Speed ◽  
Ultrasonic Waves ◽  
Minimum Size ◽  
Ultrasonic Echo ◽  
Control Technologies ◽  
Soldered Joint

Abstract High reliability requirements are imposed on the quality of the soldered joints. Typical defects in the soldered joints of heat exchangers are non-soldered. The minimum size of the non-penetration area that must be detected is about 1 square millimeter. The existing assessment of the quality of soldering is reduced to destructive tests. These tests include hydraulic and pneumatic tests. There are control technologies that use non-destructive methods. For example, the applicability of the ultrasonic echo method based on thermo-optical (laser) excitation of ultrasonic waves has been proven. However, continuous inspection of the liquid-propellant engine chamber using the traditional echo method is not rational, since the inspection speed is limited by the size of detected defects (1 square millimeter) and amounts to a few millimeters per minute. In order to increase the scanning speed without losing the ability to reliably detect defects such as “non-soldered”, it is proposed to use phased array antennas (PA) as a means of implementing the ultrasonic echo method. The paper considers the issues related to the interpretation of the information obtained when scanning the soldered joint, as well as issues related to modeling the acoustic field in the model of the soldered joint of the heat exchanger.

scholarly journals Porosity Analysis of Additive Manufactured Parts Using CAQ Technology

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1142
Author(s):  
Peter Pokorný ◽  
Štefan Václav ◽  
Jana Petru ◽  
Michaela Kritikos
Keyword(s):  
Manufacturing Process ◽  
Scanning Speed ◽  
Additive Technologies ◽  
Integration Time ◽  
Detector Resolution ◽  
Porosity Analysis ◽  
3D Scans ◽  
Printing Direction ◽  
Non Destructive

Components produced by additive technology are implemented in various spheres of industry, such as automotive or aerospace. This manufacturing process can lead to making highly optimized parts. There is not enough information about the quality of the parts produced by additive technologies, especially those made from metal powder. The research in this article deals with the porosity of components produced by additive technologies. The components used for the research were manufactured by the selective laser melting (SLM) method. The shape of these components is the same as the shape used for the tensile test. The investigated parts were printed with orientation in two directions, Z and XZ with respect to the machine platform. The printing strategy was “stripe”. The material used for printing of the parts was SS 316L-0407. The printing parameters were laser power of 200 W, scanning speed of 650 mm/s, and the thickness of the layer was 50 µm. A non-destructive method was used for the components’ porosity evaluation. The scanning was performed by CT machine METROTOM 1500. The radiation parameters used for getting 3D scans were voltage 180 kV, current 900 µA, detector resolution 1024 × 1024 px, voxel size 119.43 µm, number of projections 1050, and integration time 2000 ms. This entire measurement process responds to the computer aided quality (CAQ) technology. VG studio MAX 3.0 software was used to evaluate the obtained data. The porosity of the parts with Z and XZ orientation was also evaluated for parts’ thicknesses of 1, 2, and 3 mm, respectively. It has been proven by this experimental investigation that the printing direction of the part in the additive manufacturing process under question affects its porosity.

Optimal Parameter Design of Solder Residue in Flip Chip Process by Using Taguchi Method

2010 ◽  
Vol 443 ◽  
pp. 543-548
Author(s):  
Jian Long Kuo ◽  
Kai Lun Chao ◽  
Chun Cheng Kuo
Keyword(s):  
Taguchi Method ◽  
Product Quality ◽  
Manufacturing Process ◽  
Flip Chip ◽  
Optimal Parameter ◽  
Experimental Testing ◽  
Signal To Noise Ratio ◽  
Optimal Solution ◽  
Passive Component

Because the solder residue was found in the manufacturing process which greatly affected the product quality, the purpose of this paper was to make the product quality improved and to find an optimal solution for process parameters in the flip chip process. The experimental testing was based on SMT manufacturing process. The amount and size of solder left on passive component in the process of manufacturing were considered as the quality traits. Since too many solders left on the passive component side during flux cleaning process, it was possible that the balling would be flowed into the chip, which caused the bump short in the chip and affected the quality of the product. In this paper, orthogonal array by using Taguchi method is adopted as the effective experimental method with the least experimental runs. Also, based on the quality evaluation of signal-to-noise ratio, the ANOVA is used to evaluate the effects of quality target according to the experimental results. The results reveal that the optimization in the process is confirmed. Therefore, this study can effectively improve the solder residue in semiconductor manufacturing process.

The Application of S7-200 PLC Reactive Compensation Device in Small Substation

2012 ◽  
Vol 479-481 ◽  
pp. 1476-1480
Author(s):  
Qing He Chu ◽  
Wen Si Cao ◽  
Zhen Nie
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
High Reliability ◽  
Reactive Power Compensation ◽  
Control Device ◽  
Reactive Compensation ◽  
Reconstruction Project ◽  
Compensation Device ◽  
And Control

In the present rural power grid reconstruction project ,according to the problems of capacitor reactive power compensation in rural small substation. Take a small substation for instance, according to its operation and control method, set the criterion of the capacitor bank switching. A new high reliability, flexible reactive power compensation control device based on s7-200 PLC is designed. It plays an important role in improving the power supply , guaranteeing the quality of voltage, reducing the loss of rural power gid.

Wireless probes for measuring vertical temperature profiles in borehole heat exchangers (BHEs)

2021 ◽  
Author(s):  
Simon Schüppler ◽  
Roman Zorn ◽  
Hagen Steger ◽  
Philipp Blum
Keyword(s):  
Measurement Uncertainty ◽  
Fiber Optics ◽  
Heat Exchangers ◽  
Measurement Errors ◽  
High Reliability ◽  
Temperature Profiles ◽  
Measured Temperature ◽  
Distributed Temperature Sensing ◽  
Vertical Temperature ◽  
Borehole Heat Exchangers

<p>The measurement of the undisturbed ground temperature (UGT) serves to design low-temperature geothermal systems, in particular borehole heat exchangers (BHEs), and to monitor shallow aquifers. Wireless and miniaturized probes such as the Geosniff (GS) measurement sphere, which are characterized by an autarkic energy supply and equipped with pressure and temperature sensors, are increasingly being used for the measurement of highly resolved vertical temperature profiles. The measurement probe sinks along the course of the BHE with a selectable measurement frequency to the bottom of the BHE and is useable for initial measurements as well as long term groundwater monitoring. To ensure quality assurance and further improvement of this emerging technology, the analysis of measurement errors and uncertainties of wireless temperature measurements (WTMs) is indispensable. Thus, we provide an empirical laboratory analysis of random, systematic, and dynamic measurement errors, which lead to the measurement uncertainty of WTMs using the GS as a representative device. We subsequently transfer the analysed uncertainty to measured vertical temperature profiles of the undisturbed ground at a BHE site in Karlsruhe, Germany. The precision and accuracy of 0.011 K and -0.11 K, respectively, ensure a high reliability of the GS measurements. The largest measurement uncertainty is obtained within the first five meters of descent resulting from the thermal time constant τ of 4 s. The measured temperature profiles are qualitatively compared with common Distributed Temperature Sensing (DTS) using fiber optic cables and punctual Pt-100 sensors. Wireless probes are also suitable to correct temperature profiles recorded with fiber optics with systematic errors of up to -0.93 K. Various boundary conditions such as the inclination of the BHE pipes or changes of the viscosity and density of the BHE fluid effect the descent rate of the GS of up to 40 %. We additionally provide recommendations for technical implementations of future measurement probes and contribute to an improved understanding and further development of WTMs.</p>

Experimental study of mild steel cutting process by using the plasma arc method

2021 ◽  
Vol 108 (2) ◽  
pp. 75-85
Author(s):  
H.M. Magid
Keyword(s):  
Industrial Process ◽  
Scanning Speed ◽  
Cutting Parameters ◽  
Operating Conditions ◽  
Kerf Width ◽  
Cutting Process ◽  
Plasma Cutting ◽  
Plasma Arc ◽  
Cutting Equipment

Purpose: In this study, plasma arc cutting (PAC) is an industrial process widely used for cutting various away types of metals in several operating conditions. Design/methodology/approach: It is carried out a systematic or an authoritative inquiry to discover and examine the fact, the plasma cutting process is to establish the accuracy and the quality of the cut in this current paper assessed a good away to better the cutting process. Findings: It found that the effect of parameters on the cutting quality than on the results performed to accomplish by statistical analysis. Research limitations/implications: The objective of the present work paper is to achieve cutting parameters, thus the quality of the cutting process depends upon the plasma gas pressure, scanning speed, cutting power, and cutting height. Practical implications: The product of the plasma cutting process experimentally has been the quality of the cutting equipment that was installed to monitor kerf width quality by exam the edge roughness, kerf width, and the size of the heat-affected zone (HAZ). Originality/value: The results reveal that were technically possessed of including all the relevant characteristics, then a quality control for the cutting and describe the consequence of the process parameters.

Liquation and Crystallization Cracks in Aluminum Alloy AA2024 during Selective Laser Melting

2021 ◽  
Vol 410 ◽  
pp. 203-208
Author(s):  
I.S. Loginova ◽  
N.A. Popov ◽  
A.N. Solonin
Keyword(s):  
Aluminum Alloy ◽  
Selective Laser Melting ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Melting Zone ◽  
Alloying Elements ◽  
Laser Melting ◽  
Laser Scanning Speed ◽  
Positive Effect

In this work we studied the microstructure and microhardness of standard AA2024 alloy and AA2024 alloy with the addition of 1.5% Y after pulsed laser melting (PLM) and selective laser melting (SLM). The SLM process was carried out with a 300 W power and 0.1 m/s laser scanning speed. A dispersed microstructure without the formation of crystallization cracks and low liquation of alloying elements was obtained in Y-modified AA2024 aluminum alloy. Eutectic Al3Y and Al8Cu4Y phases were detected in Y-modified AA2024 aluminum alloy. It is led to a decrease in the formation of crystallization cracks The uniform distribution of alloying elements in the yttrium-modified alloy had a positive effect on the quality of the laser melting zone (LMZ) and microhardness.

scholarly journals Assessment of neuropsychiatric symptoms in dementia: Toward improving accuracy

2013 ◽  
Vol 7 (3) ◽  
pp. 244-251 ◽  
Author(s):  
Florindo Stella
Keyword(s):  
Rating Scale ◽  
High Reliability ◽  
Neuropsychiatric Symptoms ◽  
Clinical Approach ◽  
Behavioral Disturbances ◽  
Versatile Tool ◽  
Clinician Rating ◽  
Improving Accuracy ◽  
Elderly Caregivers

ABSTRACT The issue of this article concerned the discussion about tools frequently used tools for assessing neuropsychiatric symptoms of patients with dementia, particularly Alzheimer's disease. The aims were to discuss the main tools for evaluating behavioral disturbances, and particularly the accuracy of the Neuropsychiatric Inventory - Clinician Rating Scale (NPI-C). The clinical approach to and diagnosis of neuropsychiatric syndromes in dementia require suitable accuracy. Advances in the recognition and early accurate diagnosis of psychopathological symptoms help guide appropriate pharmacological and non-pharmacological interventions. In addition, recommended standardized and validated measurements contribute to both scientific research and clinical practice. Emotional distress, caregiver burden, and cognitive impairment often experienced by elderly caregivers, may affect the quality of caregiver reports. The clinician rating approach helps attenuate these misinterpretations. In this scenario, the NPI-C is a promising and versatile tool for assessing neuropsychiatric syndromes in dementia, offering good accuracy and high reliability, mainly based on the diagnostic impression of the clinician. This tool can provide both strategies: a comprehensive assessment of neuropsychiatric symptoms in dementia or the investigation of specific psychopathological syndromes such as agitation, depression, anxiety, apathy, sleep disorders, and aberrant motor disorders, among others.

THE EFFECT OF LIQUID SUCTION HEAT EXCHANGER SUB-COOLER ON PERFORMANCE OF A FREEZER USING R404A AS WORKING FLUID

2015 ◽  
Vol 76 (11) ◽  
Author(s):  
Muhammad Nuriyadi ◽  
Sumeru Sumeru ◽  
Henry Nasution
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cooling Capacity ◽  
Experimental Results ◽  
Working Fluid ◽  
Liquid Line ◽  
Cabin Temperature

This study presents the effect of liquid-suction heat exchangers (LSHX) sub-cooler in a freezer. The LSHX sub-cooler is a method to increase the cooling capacity of the evaporator by lowering temperature at the condenser outlet. The decrease in temperature of the condenser outlet will cause a decrease in the quality refrigerant entering the evaporator. The lower the quality of the refrigerant entering the evaporator, the higher the cooling capacity produced by the evaporator. The LSHX sub-cooler utilizes a heat exchanger to transfer heat from the outlet of the condenser (liquid line) to the suction of the compressor. In the present study, three different LSHX sub-coolers in the freezer with cabin temperature settings of 0, -10 and -20oC were investigated. The results showed that the lowest and the highest of effectiveness of the heat exchanger were 0.28 and 0.58, respectively. The experimental results also showed that EER reduction is occurred at the cabin temperature setting of 0oC and -10oC, whereas the EER improvements were always occurred at the cabin temperature settings of -20oC.

scholarly journals Cluster-Based Cooperative Cache Deployment and Coded Delivery Strategy in C-V2X Networks

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Haizhou Bao ◽  
Yiming Huo ◽  
Chuanhe Huang ◽  
Xiaodai Dong ◽  
Wanyu Qiu
Keyword(s):  
High Reliability ◽  
Cluster Head ◽  
Cluster Method ◽  
Response Delay ◽  
Delivery Strategy ◽  
Network Load ◽  
Cooperative Cache ◽  
Dynamic Topology ◽  
Cache Hit Ratio

Cellular vehicle-to-everything- (C-V2X-) based communications can support various content-oriented applications and have gained significant progress in recent years. However, the limited backhaul bandwidth and dynamic topology make it difficult to obtain the multimedia service with high-reliability and low-latency communication in C-V2X networks, which may degrade the quality of experience (QoE). In this paper, we propose a novel cluster-based cooperative cache deployment and coded delivery strategy for C-V2X networks to improve the cache hit ratio and response time, reduce the request-response delay, and improve the bandwidth efficiency. To begin with, we design an effective vehicle cluster method. Based on the constructed cluster, we propose a two-level cooperative cache deployment approach to cache the frequently requested files on the edge nodes, LTE evolved NodeB (eNodeB) and cluster head (CH), to maximize the overall cache hit ratio. Furthermore, we propose an effective coded delivery strategy to minimize the network load and the ratio of redundant files. Simulation results demonstrate that our proposed method can effectively reduce the average response delay and network load and improve both the hit ratio and the ratio of redundant files.

scholarly journals The Euro-Mediterranean Tsunami Catalogue

2014 ◽  
Vol 57 (4) ◽  
Author(s):  
Alessandra Maramai ◽  
Beatriz Brizuela ◽  
Laura Graziani
Keyword(s):  
High Reliability ◽  
Tsunami Hazard ◽  
Historical Documents ◽  
Complex Task ◽  
Detailed Review ◽  
Additional Information ◽  
Documentary Sources ◽  
Hazard And Risk ◽  
Hazard And Risk Assessment

<p>A unified catalogue containing 290 tsunamis generated in the European and Mediterranean seas since 6150 B.C. to current days is presented. It is the result of a systematic and detailed review of all the regional catalogues available in literature covering the study area, each of them having their own format and level of accuracy. The realization of a single catalogue covering a so wide area and involving several countries was a complex task that posed a series of challenges, being the standardization and the quality of the data the most demanding. A “reliability” value was used to rate equally the quality of the data for each event and this parameter was assigned based on the trustworthiness of the information related to the generating cause, the tsunami description accuracy and also on the availability of coeval bibliographical sources. Following these criteria we included in the catalogue events whose reliability ranges from 0 (“very improbable tsunami”) to 4 (“definite tsunami”). About 900 documentary sources, including historical documents, books, scientific reports, newspapers and previous catalogues, support the tsunami data and descriptions gathered in this catalogue. As a result, in the present paper a list of the 290 tsunamis with their main parameters is reported. The online version of the catalogue, available at http://roma2.rm.ingv.it/en/facilities/data_bases/52/catalogue_of_the_euro-mediterranean_tsunamis, provides additional information such as detailed descriptions, pictures, etc. and the complete list of bibliographical sources. Most of the included events have a high reliability value (3= “probable” and 4= “definite”) which makes the Euro-Mediterranean Tsunami Catalogue an essential tool for the implementation of tsunami hazard and risk assessment.</p>

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