Experimental evaluation of step-by-step and continuous flaring methods for fixing thick-walled tubes in thick tubesheets

2021 ◽  
pp. 101-108
Author(s):  
А.В. Санников
Keyword(s):  
Radial Distribution ◽  
Heat Exchangers ◽  
Experimental Evaluation ◽  
Quantitative Assessment ◽  
High Probability ◽  
Screw Rolling ◽  
Actual Problem ◽  
Entire Thickness ◽  
Time Required

В работе рассматривается актуальная задача крепления толстостенных труб в толстых трубных решетках в теплообменных аппаратах. В настоящее время в теплообменных аппаратах с толстыми трубными решетками широко применяются так называемые комбинированные соединения, изготовление которых предусматривает предварительную развальцовку концов труб на конус, сварку концов труб с трубной решеткой и последующую радиальную раздачу труб на всю толщину трубной решетки. В работе проведена оценка технических возможностей пошаговых и ленточно-винтовых вальцовок при развальцовке толстостенных труб в толстых трубных решетках. Дано сравнение качества образцов соединений по критериям герметичности, прочности и состоянию поверхностей на развальцованных участках труб, полученных двумя различными способами развальцовки: пошаговым и непрерывным. Приведена сравнительная количественная оценка затрат времени, требуемого для развальцовки труб тем или иным способом. В процессе развальцовки труб в образцах было установлено, что как пошаговые, так и ленточно-винтовые вальцовки способны развальцовывать толстостенные трубы с соотношением внутреннего и наружного диаметров близким к 0,66 (если это отношение меньше 0,66, то такие трубы принято считать «невальцуемыми»). В результате исследований установлено, что вальцовки ЛВК могут успешно применяться для закрепления особо толстостенных труб малых диаметров в толстых трубных решетках, для которых применение пошаговых вальцовок может быть проблематичным из-за высокой вероятности поломки (скручивания) веретен. The paper considers the actual problem of fixing thick-walled tubes in thick tubesheets in heat exchangers. Currently, so-called combined joints are widely used in heat exchangers with thick tubesheets, the manufacture of which provides for pre-rolling the ends of the tubes into a cone, welding the ends of the tubes with a tubesheet and subsequent radial distribution of tubes to the entire thickness of the tubesheet. The paper evaluates the technical capabilities of step-by-step and band-screw rolling when rolling thick-walled tubes in thick tubesheets. The quality of joint samples is compared according to the criteria of tightness, strength and condition of surfaces on the rolled sections of tubes obtained by two different methods of expanding: step-by-step and continuous. A comparative quantitative assessment of the time required for tube expanding in one way or another is given. In the process of expanding tubes in the samples, it was found that both step-by-step and tape-screw rolling rolls are able to roll thick-walled tubes with a ratio of internal and external diameters close to 0.66 (if this ratio is less than 0.66, then such tubes are considered "non-expanding". As a result of the research, it is proved that LVK rollers can be successfully used for fixing especially thick-walled tubes, for which the use of step-by-step rollers can be problematic due to the high probability of breakage (twisting) of the spindles.

Construction Control As A Strategy For Improving The Quality Of Buildings And Structures

2020 ◽  
Keyword(s):  
Quality Control ◽  
Life Cycle ◽  
Construction Control ◽  
Construction Sites ◽  
Actual Problem ◽  
Construction Market ◽  
Construction Products ◽  
Underlying Causes ◽  
Required Quality

In construction production, the safety of constructing buildings and structures is achieved by ensuring the required quality as a result of systematic construction control based on the implementation of a complex of technical, economic and organizational measures at all stages of the object's life cycle. The article deals with the actual problem of improving the quality of construction products-buildings and structures in conjunction with the activities of construction control bodies. The article presents the advanced foreign and domestic experience of ensuring the quality control at the construction sites, providing for the prevention of the underlying causes of defects and increasing the interest of the contractors directly. On the basis of the analysis of the current situation with quality control at the construction market, ways to improve its efficiency by developing a unified system of technological implementation of relevant requirements for the quality of construction products, determining the rational number and business load of construction control engineers, as well as the active activities of self-regulatory organizations in this area are offered.

Heat Transfer Enhancement in Separation Process of Ethanol from Ethanol Water Mixture by Using Surfactants

2020 ◽  
pp. 9-14 ◽  
Author(s):  
Acharya Anil Ramchandra ◽  
R. Kadam ◽  
A. T. Pise
Keyword(s):  
Heat Transfer ◽  
Ammonium Chloride ◽  
Sodium Dodecyl ◽  
Water Mixture ◽  
Transfer Enhancement ◽  
Surface Tension Reduction ◽  
Surface Active Agents ◽  
Surface Active ◽  
Time Required

Here the investigations are done while distillation of ethanol-water mixture for separating ethanol from fermentation process. Focus is to study reduction in time required and hence saving in energy for the distillation process of ethanol-water mixture under the influence of surface-active agents (Surfactants). This novelty is from observation of these surfactants to enhance heat transfer rate because of surface tension reduction in aqueous solutions. SDS (Sodium Dodecyl Sulphate), NH4Cl (Ammonium Chloride) and SLBS (Sodium lauryl benzene sulphonate) surfactants in different concentration are experimented. The concentration of these surfactant is varied from 1700 ppm to 2800 ppm. This range is decided by observing critical micelle concentration of used surfactants. Results showed that time is reduced and hence energy consumption is also reduced. Results shown by NH4Cl are found to be more useful as it is ecofriendly surfactant which is not affecting ethanol-water mixture. Use of ammonium chloride as surfactant in distillation is actually useful to reduce energy without hampering the quality of process is the novelty of this work.

scholarly journals Public Awareness and Disaster Risk Reduction: Just-in-Time Networks and Learning

2008 ◽  
Vol 23 (3) ◽  
pp. 286-288 ◽  
Author(s):  
Ali Ardalan ◽  
Faina Linkov ◽  
Eugene Shubnikov ◽  
Ronald E. LaPorte
Keyword(s):  
Hurricane Katrina ◽  
Wide Spectrum ◽  
Public Awareness ◽  
Just In Time ◽  
Educational Levels ◽  
Hazard And Risk ◽  
Time Required ◽  
Expert Network ◽  
Core Materials

AbstractImproving public awareness through education has been recognized widely as a basis for reducing the risk of disasters. Some of the first disaster just-in-time (JIT) education modules were built within 3–6 days after the south Asia tsunami, Hurricane Katrina, and the Bam, Pakistan, and Indonesia earthquakes through a Supercourse. Web monitoring showed that visitors represented a wide spectrum of disciplines and educational levels from 120 developed and developing countries. Building disaster networks using an educational strategy seizes the opportunity of increased public interest to teach and find national and global expertise in hazard and risk information. To be effective, an expert network and a template for the delivery of JIT education must be prepared before an event occurs, focusing on developing core materials that could be customized rapidly, and then be based on the information received from a recent disaster. The recyclable process of the materials would help to improve the quality of the teaching, and decrease the time required for preparation. The core materials can be prepared for disasters resulting from events such as earthquakes, hurricanes, tsunamis, floods, and bioterrorism.

Method of experimental evaluation of the efficiency coefficient of vibration protection of the rope-rod coupling "MAMSAR+A" of the diesel generator set DGA-8.83

2021 ◽  
pp. 88-95
Author(s):  
М.А. Минасян ◽  
А.М. Минасян ◽  
Ц. Цзэн
Keyword(s):  
Experimental Evaluation ◽  
Vibration Isolation ◽  
Experimental Studies ◽  
Original Method ◽  
Efficiency Coefficient ◽  
Diesel Generator ◽  
Vibration Protection ◽  
Rigid Connection ◽  
Two Stages

Объектом исследования является опытный образец запатентованной канатностержневой муфты (КСМ) «MAMSAR+А» в качестве привода дизель-генераторного агрегата ДГА-8,83 мощностью 9,56 кВт при частоте вращения 1500 мин-1 с дизелем 2Ч 8,5/11 и генератором «ГК-5,6». Целью исследования является экспериментальная оценка коэффициента эффективности вибрационной защиты КСМ. Поставленная цель достигается разработкой и реализацией оригинальной методики экспериментальной оценки коэффициента эффективности КСМ с анализом и выводами результатов экспериментальных исследований. Экспериментальные исследования проводятся в два этапа. Первый этап – с упругим соединением КСМ, второй этап – с жестким соединением. Оригинальность методики экспериментальной оценки коэффициента эффективности вибрационной защиты КСМ главным образом заключается в том, что между двумя этапами экспериментальных исследований КСМ не демонтируется. Следовательно, качество центровки не нарушается. Усредненный коэффициент эффективности виброизоляции КСМ составляет от 3 до 8 дБ. The object of this research is a prototype of the patented wire rope coupling (KSM) "MAMSAR+A" as a drive for a diesel-generator unit DGA-8.83 with a power of 9.56 kW at a speed of 1500 min-1 with a 2CH 8.5/11 diesel engine and a generator "KG-5.6". The aim of the research is to experimentally evaluate the efficiency coefficient of vibration protection of the KSM. This goal is achieved by developing and implementing an original method for experimental evaluation the efficiency coefficient of the KSM with analysis and conclusions of the results of experimental studies. Experimental studies are conducted in two stages. The first stage - with an elastic connection of the coupling, the second stage - with a rigid connection. The originality of the method of experimental evaluation of the efficiency coefficient of vibration protection of the KSM mainly lies in the fact that the KSM is not dismantled between the two stages of experimental research. Therefore, the quality of alignment is not violated. The average coefficient of vibration isolation efficiency of the KSM is from 3 to 8 dB.

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.

Development of laboratory x-ray fluorescence holography equipment

2003 ◽  
Vol 18 (6) ◽  
pp. 1471-1473 ◽  
Author(s):  
Yukio Takahashi ◽  
Kouichi Hayashi ◽  
Kimio Wakoh ◽  
Naomi Nishiki ◽  
Eiichiro Matsubara
Keyword(s):  
Single Crystal ◽  
Count Rate ◽  
Detection System ◽  
High Count ◽  
Synchrotron Source ◽  
High Count Rate ◽  
X Ray ◽  
Graphite Monochromator ◽  
Time Required

Laboratory x-ray fluorescence holography equipment was developed. A single-bent graphite monochromator with a large curvature and a high-count-rate x-ray detection system were applied in this equipment. To evaluate the performance of this equipment, a hologram pattern of a gold single crystal was measured. It took two days, which was about one-third the time required for the previous measurements using the conventional x-ray source and several times that using the synchrotron source. The quality of the hologram pattern is as good as that obtained using the synchrotrons. Clear atomic images on (002) are reconstructed.

scholarly journals Mathematical models and a constructive heuristic for finding minimum fundamental cycle bases

2005 ◽  
Vol 15 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Leo Liberti ◽  
Edoardo Amaldi ◽  
Francesco Maffioli ◽  
Nelson Maculan
Keyword(s):  
Linear Programming ◽  
Total Cost ◽  
Fundamental Cycle ◽  
Cycle Basis ◽  
Cpu Time ◽  
Constructive Heuristic ◽  
Cycle Bases ◽  
Time Required ◽  
Application Fields

The problem of finding a fundamental cycle basis with minimum total cost in a graph arises in many application fields. In this paper we present some integer linear programming formulations and we compare their performances, in terms of instance size, CPU time required for the solution, and quality of the associated lower bound derived by solving the corresponding continuous relaxations. Since only very small instances can be solved to optimality with these formulations and very large instances occur in a number of applications, we present a new constructive heuristic and compare it with alternative heuristics.

scholarly journals POPULATION AS AN INTEGRAL PART OF RECREATIONAL AND TOURIST POTENTIAL

2021 ◽  
Vol 51 (2) ◽  
pp. 101-108
Author(s):  
Oleksandr Topchiyev ◽  
Vitalii Sych ◽  
Viktoriya Yavorska ◽  
Katerina Kolomiyets
Keyword(s):  
Quality Of Life ◽  
Anthropogenic Load ◽  
Economic Activities ◽  
Actual Problem ◽  
Big City ◽  
Objective Basis ◽  
Resource Characteristics ◽  
Recreation And Tourism

The article defines the directions that it is recommended to assess the role of the population in the formation of recreation and tourism activities (RTA). It is proved the need to investigate the role of the population in the RTA in two main directions: 1) as a subject of recreational and tourist systems in its relation to their media (objects); 2) combined - as a subject and component of the object of recreational and tourist systems. The population forms the flows of recreation and tourists, developing relevant structures and mechanisms for their recreational and tourist service, organizes directions and fields of economic and non-economic activities that ensure the recreational needs of the population, creates a specialized recreation infrastructure, develops and implements a variety of functional and territorial organization of recreation and tourism, forms at the national and international level of territorial division of labor. In order to evaluate the recreational potential of a separate plot or object usually consider not the entire nomenclature of conditions and resources, but only a characteristic or typical combination. Each territory, each object of recreation and tourism has its own set (complex) of resource characteristics. And this circumstance greatly facilitates the procedure for a comprehensive assessment of recreational potential due to elimination (allocation) of a characteristic complex of terms and resources of RTA. A similar situation arises for a functional assessment of recreational potential. The valuation of conditions and resources are not developed for a general list of species and forms of RTA, but for those that are distributed in this area in this locality. It is determined that among the numerous characteristics and indicators of recreational potential, the concept of recreational and tourist attractiveness is one of the objective indicators of resource potential. Estimation of recreational potential for quantitative indicators of recreation and tourists and their numerical and spatial distributions creates an objective basis for all other characteristics and indicators of RTD. Another important characteristic of the recreational potential, which forms the population as a factor of RTA is a recreation capacity of territories and objects of RTA. The concept of "recreational capacity" is related to "recreational attractiveness". Attractiveness characterizes recreational territories and objects for their attraction, according to real flows of recreation and tourists. Recreational capacity is intended to set the upper limits of such attractiveness. Attractiveness represents the actual use of a recreational resource, and the capacity indicates its critical level of recreation, which does not lead to degradation of this resource. In recreational geography, tourism and planning of territories, this direction is well known and extremely designed. The indicators of recreational capacities for certain types and recreation forms and recreations - beach baths, short-term rest in green zones, anthropogenic load of resort zones and areas of the natural reserve fund, maximum population density in various functional zones of the big city, etc. At the same time, the zonal principles of assessing the recreational capacity of objects and areas of recreation and tourism have not yet been developed, and this actual problem is waiting for its researchers. The population forms a so-called anthropogenic load on the territory, and its economic activity is man-made load. Anthropogenic-technogenic load is considered as a factor of recreational and tourist activities, in turn, indicators of anthropogenic-technogenic load are the original characteristics of "anti-resource" of recreation potential. The article has proven that in the context of the study of the prerequisites for the development of recreation and tourist activities of the region also need to analyze both the quality of life of the population, in addition to the assessment of this indicator have a high contrast and diversity in the country. Key words: population, recreational and tourist potential, attractiveness of recreational territories, anthropogenic-technogenic load, quality of life of the population.

scholarly journals IPG as a new method to improve the agility of the initial analysis of the inventive design

2021 ◽  
Vol 49 (3) ◽  
pp. 549-562
Author(s):  
Masih Hanifi ◽  
Hicham Chibane ◽  
Rémy Houssin ◽  
Denis Cavallucci
Keyword(s):  
Inverse Problem ◽  
Design Method ◽  
New Method ◽  
Significant Progress ◽  
Initial Analysis ◽  
The Subject ◽  
Time Required

TRIZ method has long proven its value without appearing to the industrial world as inevitable. Design researchers have therefore addressed the limitations of the TRIZ method and have overcome them with more systematic approaches. Among these, the Inventive Design Method (IDM) has been the subject of several articles and put into practice in the industry. It is considered an improvement over TRIZ but still suffers from some drawbacks in terms of the time-consuming nature of its implementation. We focused on the IDM process by trying to both identify its areas of inefficiencies while attempting to preserve the quality of its deliverables. Our approach consists of applying the precepts of Lean to IDM. The result is the Inverse Problem Graph (IPG) method, inspired by IDM, but offering significant progress in reducing the time required to mobilize experts while preserving its inventive outcomes. This article outlines our approach for the construction of this new method.

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