scholarly journals Reliability of the belt conveyor bed when restoring failed roller supports

2021 ◽  
Vol 942 (1) ◽  
pp. 012002
Author(s):  
M A Listova ◽  
V V Dmitrieva ◽  
P E Sizin
Keyword(s):  
Mathematical Expectation ◽  
Recovery Rate ◽  
Structural Elements ◽  
Kolmogorov Equations ◽  
Belt Conveyor ◽  
First Case ◽  
Working Roller ◽  
Belt Conveyors ◽  
High Level ◽  
Roller Support

Abstract The reliability of modern belt conveyors, whose length reaches tens of kilometers, is primarily determined by the reliability of the roller supports that support the belt and ensure its movement. As they wear out, some roller bearings fail and need to be repaired or replaced. The dynamics of the number of working roller supports is determined by the system of Kolmogorov equations. Their solution allows us to find the probabilities of finding the system in states with a different number of working elements. The article finds probabilities for two cases. In the first case, when restoring, only one roller support is repaired each time. In the second case, all roller supports are repaired or replaced. In the case of sequential recovery, the mathematical expectation of the number of properly working roller supports may be less than the total number by several units. There are always elements that need to be repaired. If the recovery rate of the elements is many times higher than the failure rate, the mathematical expectation of the number of properly operating roller supports is less than the total number of roller supports by less than one, during most of the time all roller supports are serviceable. In the case of simultaneous recovery of elements, an equally high level of reliability is achieved even with comparable failure and recovery rates. The results obtained can be used to determine the necessary reserve of spare structural elements and to plan the maintenance of conveyors.

Application the Renewal Theory to Determining the Models of the Optimal Lifetime for Conveyor Belts

2014 ◽  
Vol 683 ◽  
pp. 97-101
Author(s):  
Anna Grinčová ◽  
Miriam Andrejiová ◽  
Peter Grendel
Keyword(s):  
Renewal Theory ◽  
Conveyor Belt ◽  
Transport Systems ◽  
Belt Conveyor ◽  
Operation Analysis ◽  
Conveyor Belts ◽  
Belt Conveyors ◽  
High Level ◽  
The Cost ◽  
Methods Of Operation

Belt conveyance belongs to the continual transport systems characteristic with high-level conveying performances. Belt conveyors are of significant importance in the transportation of various types of materials in the industries like engineering, metallurgy and construction. The fundamental and the most expensive component of belt conveyors is the conveyor belt which is, during the operation on the belt conveyor, exposed to number of various loads that evoke the process of conveyor belt wear and damage. Lifetime of conveyor belts, which is the determining parameter for the belt conveyance economy and efficiency, is very important for the practice.Issues regarding the conveyor belt lifetime should be solved applying also the methods of operation analysis, especially the linear programming and the renewal theory that uses the theory of probability and mathematic statistics. The objective of our research was to determine the optimal lifetime (optimal performance duration) of a belt conveyor, applying the renewal theory, whereas the research was based on the cost approach of the renewal process.

Jewish Holiday “Tu Bishvat” or Two Cases of Small Bowel Obstruction with Dried Apricot

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Kukeev I ◽  
◽  
Replyansky I ◽  
Czeiger D ◽  
Atias S ◽  
...  
Keyword(s):  
Small Bowel ◽  
Small Bowel Obstruction ◽  
Bowel Obstruction ◽  
Gastric Bypass Surgery ◽  
Surgical Removal ◽  
Cellulose Content ◽  
Lead Point ◽  
First Case ◽  
Dried Fruit ◽  
High Level

Introduction: Small bowel obstruction caused by bezoars is rare. One of the causes of phytobezoars is dried fruits. We present two cases of small bowel obstruction caused by dried apricots during Jewish holiday “Tu BiShvat”. Case Presentation: Two men, 54 and 86 years old hospitalized with acute abdomen attributed to small bowel obstruction. In the first case - intoxicated patient, due to suspicion of mesenteric ischemia underwent laparotomy. A lead point caused obstruction was found and after enterotomy whole dried apricot was removed. The patient swallowed it whole three days before hospitalization. In the second case, edentulous patient with small bowel obstruction and peritonitis underwent laparotomy. The cause of obstruction was a dried apricot swallowed whole by the patient. Discussion: Presentation of bezoar with features of acute surgical abdomen is extremely rare, accounting for only 1% of the patients. The expansion of phytobezoar that is high in cellulose content can absorb a large amount of fluid causing an obstruction of the small bowel. The treatment of small bowel obstruction caused by bezoars varies from dissolving with cellulase, papain and even Coca-Cola, followed by endoscopic and surgical removal. Conclusion: A high level of suspicion needs to exist in the presence of a history of eating dried fruit, which can cause gastrointestinal obstruction. Especially on background gastric bypass surgery and inadequate mastication.

scholarly journals A Case of Multiple Posterior Intercostal Artery Common Trunks in Conjunction with Additional Arterial Variations

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Nicholas R. Fanselow ◽  
Nolan Wallace ◽  
Daniel Sehi ◽  
Lokesh Coomar ◽  
John Martin ◽  
...  
Keyword(s):  
Vertebral Artery ◽  
Intercostal Space ◽  
Thoracic Wall ◽  
Thoracic Cavity ◽  
Arterial Variation ◽  
Arterial Variations ◽  
First Case ◽  
Male Cadaver ◽  
The Right ◽  
High Level

Several thoracic vasculature variations were observed in an 81-year-old male cadaver during routine dissection. These included 5 common trunks of posterior intercostal arteries, a descending branch of the right vertebral artery, and atypical neurovascular relationships within intercostal spaces. On the right side, two common trunks of posterior intercostal arteries were observed supplying the 4th-7th intercostal spaces and 9th-11th intercostal spaces, respectively. There was also a small accessary branch supplying the 9th intercostal space. The first three posterior intercostal spaces on the right were supplied by a descending branch of the vertebral artery. On the left side, three common trunks of posterior intercostal arteries were encountered, supplying intercostal spaces 3-5, 6-7, and 11 plus the subcostal space. An atypical neurovascular relationship was observed in the right 6th intercostal space, as well as the left 2nd, 3rd, and 6th intercostal spaces. This is the first case report that presents 5 common trunks of posterior intercostal arteries, as well as common trunks in conjunction with other arterial variation in the posterior thoracic wall. These variations carry a high level of clinical significance and may be helpful in guiding decision-making related to surgical procedures related to the posterior thoracic cavity and spine.

scholarly journals Effect of tsunami load on the elementary school building of the 23/24 Padang, Indonesia

2021 ◽  
Vol 331 ◽  
pp. 07016
Author(s):  
Fauzan Fauzan ◽  
Khin Thu Zar Htay ◽  
Zawil Huda ◽  
Hafiz Oktaufik ◽  
Geby Aryo Agista
Keyword(s):  
Elementary School ◽  
Capital City ◽  
Seismic Load ◽  
School Building ◽  
Structural Elements ◽  
Public Buildings ◽  
Risk Zone ◽  
The Public ◽  
West Sumatra ◽  
High Level

West Sumatra Province is one of the provinces in Indonesia that is vulnerable to natural disasters, especially earthquakes and tsunamis. Padang city, as the capital city of West Sumatra, is an area that is included in an area with a high level of vulnerability (High Risk Zone) to tsunamis. Therefore, the construction of public buildings such as hospitals, government offices, and school buildings must have certain technical engineering that is able to anticipate the damage and collapse of buildings due to the earthquake and tsunami. One of the public buildings as an educational facility in Padang city is the Elementary School building of the 23/24 (SD 23/24 Padang), located close to the beach. Based on the evaluation results of the Detail Engineering Design (DED) documents, it is found that this building was designed without taking into account the tsunami loads. Therefore, a building assessment should be carried out to check the capacity of the building to resist the working loads, including the tsunami loads, and to investigate the effect of the tsunami loads on the SD 23/24 Padang building. In this study, the building was analyzed using ETABS v.18 software based on the new Indonesian Seismic Code, SNI 1726-2019 for seismic load and FEMA P646-2019 for calculating tsunami loads. The results show that the SD 23/24 Padang building is strong against earthquake loads, but it doesn’t have enough capacity when tsunami loads are applied, in which there are several structural elements (columns/beams) that do not have sufficient capacity to withstand the combined earthquake and tsunami loads. The effect of tsunami loads on the building structure is also discussed in this paper.

Zika Virus Awareness and Prevention Practices Among University Students in Miami: Fall 2016

2018 ◽  
Vol 45 (6) ◽  
pp. 967-976 ◽  
Author(s):  
William Darrow ◽  
Chintan Bhatt ◽  
Cassandra Rene ◽  
Lakisha Thomas
Keyword(s):  
Zika Virus ◽  
World Health ◽  
Local Public Health ◽  
School Officials ◽  
Institutional Review ◽  
First Case ◽  
Blackboard Learn ◽  
Multistage Sampling ◽  
Health Organization ◽  
High Level

In January 2016, the first case of mosquito-borne Zika infection in the mainland United States was confirmed in Miami, Florida. The first locally acquired case was reported 6 months later. Local public health and school officials began warning students of the outbreak on their return to the classroom in August 2016. In November–December 2016, we conducted a survey of students attending a large public university in Miami to determine how well informed they were about Zika. A multistage sampling design was used to contact teaching assistants and ask them for help in recruiting their students. Eligible students had to be 18 years of age or older and enrolled in at least one three-credit course during fall semester. A 25-item questionnaire based on the World Health Organization Zika Knowledge, Attitudes, and Practice Resource Pack was developed, pretested, and approved by the university’s institutional review board before it was made available to eligible students through Blackboard Learn or a survey link. About half (50.4%) of the 139 respondents had heard about Zika prior to 2016. Only one student was unaware of Zika before our survey. Most (47.1%) first learned about Zika through television, 18.8% from family or friends, and 15.2% from the Internet, social media, or university e-mail. Two thirds (66.2%) believed Zika could be prevented, 15.1% thought it might be prevented, and 85.7% had taken some precautions. A high level of awareness of the risk of Zika infection was apparent. Most students reported taking steps to avoid exposure to the Zika virus.

TRACTION FORCES CREATED BY FLEXIBLE ELEMENTS AND HOISTING-AND-TRASPORT, CONSTRUCTION, ROAD VEHICLES AND EQUIPMENT SYSTEMS BY MEANS OF FRICTION. LECTURE 4

2020 ◽  
pp. 43-49 ◽  
Author(s):  
A. I. Nizhegorodov
Keyword(s):  
Belt Conveyor ◽  
Road Vehicles ◽  
Drive Power ◽  
Cable System ◽  
Euler Formula ◽  
Flexible Links ◽  
Tower Crane ◽  
Movement Mechanism ◽  
Belt Conveyors

The article consistently sets forth the material of the fourth lecture on the course “Theory of hoisting-and-transport, construction, road vehicles and equipment”, which included the following questions: transfer of traction efforts by flexible elements using the example of a thin inextensible thread, derivation of the Euler formula, flexible links and hoisting-and-transport, construction, road vehicle and equipment (HTCRVE) systems; the operation and calculation of the belt brake; the node attaching the rope to the drum and its calculation; the resistance in the cable system of the movement mechanism of the of the tower crane; the determination of the resistances in the cargo truck cable system of the movement mechanism; the transmission of traction by friction in the belt conveyors; the calculation of the drive station drive power of the belt conveyor while transmitting traction by friction.

Design of Power Supply for Mining Belt Conveyor Integrated Protection Device KHP178k-z Based on Topswitch-JX

2014 ◽  
Vol 614 ◽  
pp. 241-244
Author(s):  
Hai Zhu Yang ◽  
Zeng Liang Zhang
Keyword(s):  
Power Supply ◽  
Protection Device ◽  
Belt Conveyor ◽  
Reliable Operation ◽  
Output Waveform ◽  
Output Quality ◽  
Belt Conveyors

Mining belt conveyor integrated protection device KHP178k-z is an important device for the supervision and protection of the belt conveyors. A new power supply based on TOPSwitch-JX is designed in this paper to ensure the reliable operation of the device. Applying TOPSwitch-JX, the circuit of the power supply is simplified and the output quality is improved. Experiments show that the output waveform is stable and the ripple is small. The power supply designed is effective to meet the requirements of mining belt conveyor integrated protection device KHP178k-z.

scholarly journals Computer model of electric drive of 1L100K conveying unit

2019 ◽  
Vol 134 ◽  
pp. 01012
Author(s):  
Denis Zolkin ◽  
Vadim Petrov
Keyword(s):  
Control System ◽  
Electric Drive ◽  
Ring System ◽  
Vibration Damping ◽  
Electromechanical System ◽  
Dynamic Loads ◽  
Belt Conveyor ◽  
Electric Drives ◽  
Belt Conveyors ◽  
Elastic Elements

The paper deals with the problems of vibration damping and limiting dynamic loads in the electromechanical system of a belt conveyor by means of an adjustable electric drive. A conveying unit is represented as a three-mass ring system, which corresponds to a conveying unit with cinematically closed tape. The development of the structure of the control system for electric drives of belt conveyors with limited dynamic loads in elastic elements will reduce the dynamic loads on the belt and therefore the wear of the belts. Conditions of damping of oscillations in electromechanical system of belt conveyors are defined.

scholarly journals Determination of the loads on the rollers of the tubular belt conveyor

2019 ◽  
Vol 109 ◽  
pp. 00096
Author(s):  
Andrii Smirnov ◽  
Tamara Mishchenko
Keyword(s):  
Service Life ◽  
Ritz Method ◽  
Radius Of Curvature ◽  
Inertial Forces ◽  
Belt Conveyor ◽  
Dynamic Forces ◽  
Plates And Shells ◽  
Bulk Load ◽  
Roller Support

The article presents methods for determining loads on rollers of a six-roll support of a tubular belt conveyor, based on the equilibrium laws of elastic cylindrical plates and shells filled with a freight. In this case, the forces acting on the rollers of the tubular conveyor are the sum of the forces caused by the weight and expansion of the bulk load, the weight and bend of the belt, as well as the inertial forces associated with the curvature and the deflection of the belt under the weight of the bulk load. The dynamic forces acting on the rollers as the belt moves are determined from the equation of the oscillations of a heavy flexible string using the Ritz method. As a result of the research, analytical dependences of the forces acting on the rollers of the six-roller support of the tubular conveyor on the parameters of the conveyor, the belt, the properties of the bulk load and the radius of curvature of the conveyor are obtained, and an assessment of the component these forces is given. The results can be used to determine the parameters of the tubular conveyors rollers and increase the service life of the rollers.

Mathematical Model for Determining the Lifetime of Conveyor Belts Depending on some Selected Parameters

2014 ◽  
Vol 683 ◽  
pp. 147-152
Author(s):  
Miriam Andrejiová ◽  
Anna Grinčová ◽  
Anna Pavlisková
Keyword(s):  
Mathematical Model ◽  
Statistical Methods ◽  
Paint Layer ◽  
Conveyor Belt ◽  
Belt Conveyor ◽  
Layer Width ◽  
Conveyor Belts ◽  
Belt Conveyors ◽  
Transported Material ◽  
Optimal Construction

In the last years, belt conveyors belong to the most frequently used means of transport in various industries. The most important component of the belt conveyor is the conveyor belt. Therefore, it is necessary to pay more attention also to optimal lifetime of conveyor belts. Conveyor belt lifetime is a very complicated issue. It is affected by plenty of factors, including above all the quality structure of the belt conveyor, optimal construction, production, and properties of the conveyor belt as such, adequate solution of conveyance route shifting, reasonable maintenance, and quality repairs of conveyor belts. The paper deals with the exploring the lifetime of conveyor belts depending from on some selected parameters obtained from the operating records of practice (thickness of paint layer, width and length of the belt, conveyor speed and quantity of transported material) with using appropriate mathematical - statistical methods.

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