scholarly journals An Interactive Method to Analysis of the Response of the Different Reinforcement Structures of a Door Opening of a Wind Tower

2020 ◽  
Vol 64 (4) ◽  
pp. 263-272
Author(s):  
Mourad Belhadj ◽  
Noureddine Lahbari ◽  
Abdelkader Slimane ◽  
Djamel Aouiche
Keyword(s):  
Cylindrical Shell ◽  
Local Buckling ◽  
Stiffened Panel ◽  
Thin Cylindrical Shell ◽  
Door Opening ◽  
Extreme Load ◽  
Longitudinal Stiffeners ◽  
And Performance ◽  
The Cost ◽  
Distribution Of Stress

The aim of this work is to present a precise numerical calculus method capable to predict the behavior of a wind turbine mast, which is characterized by an open door in its lower part in order to facilitate the access to maintenance tasks. A parametric study had been conducted in this context. The structure studied of steel tower is considered a thin cylindrical shell with constant section and thickness along its studied height. The geometry of the tower had been modeled by non-linear shell type elements. Designers use interior reinforcements to avoid local buckling and minimize the disturbance of the distribution of stress in extreme conditions. The designs adopted in the models are proposed to achieve optimized results, the minimization of the mass, the maximization of the natural frequency and the rigidity at the end of the work. Many configuration had been considered in this study, the enhancement of the gap by using a panel with variable thickness value, by longitudinal stiffeners, by combined stiffeners and finally by a stiffened panel. A numerical model had been suggested to examine a cylindrical shell behavior in compression using the Abaqus software. The obtained results demonstrate the viability and performance of the proposed approach which perfectly meets the structural requirements of the wind tower. We have observed that the stiff plate model gives reliable results to stability under extreme load. On the other hand it is economically profitable is less material needed for manufacturing, which reduces the cost.

Return on Invesment (ROI) of Software Product: A Systematic Literature Review

2015 ◽  
Vol 6 (1) ◽  
pp. 50-57
Author(s):  
Rizqa Raaiqa Bintana ◽  
Putri Aisyiyah Rakhma Devi ◽  
Umi Laili Yuhana
Keyword(s):  
Return On Investment ◽  
Assessment Criteria ◽  
Software Product ◽  
And Performance ◽  
Rational Consideration ◽  
Actual Return ◽  
The Cost ◽  
Investment Models ◽  
The Impact

The quality of the software can be measured by its return on investment. Factors which may affect the return on investment (ROI) is the tangible factors (such as the cost) dan intangible factors (such as the impact of software to the users or stakeholder). The factor of the software itself are assessed through reviewing, testing, process audit, and performance of software. This paper discusses the consideration of return on investment (ROI) assessment criteria derived from the software and its users. These criteria indicate that the approach may support a rational consideration of all relevant criteria when evaluating software, and shows examples of actual return on investment models. Conducted an analysis of the assessment criteria that affect the return on investment if these criteria have a disproportionate effort that resulted in a return on investment of a software decreased. Index Terms - Assessment criteria, Quality assurance, Return on Investment, Software product

Characterisation of Static Strip Seal Flow

2007 ◽  
Author(s):  
Arash Farahani ◽  
Peter Childs
Keyword(s):  
Gas Flow ◽  
Pressure Ratio ◽  
Flow Characteristics ◽  
Main Stream ◽  
Cfd Modelling ◽  
Height Range ◽  
And Performance ◽  
Nozzle Guide ◽  
The Cost ◽  
Cooling Air

Strip seals are used in gas turbine engines between two static elements or between components which do not move relative to each other, such as Nozzle Guide Vanes (NGVs). The key role of a strip seal between NGV segments is sealing between the flow through the main stream annulus and the internal air system, a further purpose is to limit the inter-segmental movements. In general the shape of the strip seal is a rectangular strip that fits into two slots in adjacent components. The minimum clearance required for static strip seals must be found by accounting for thermal expansion, misalignment, and application, to allow correct fitment of the strip seals. Any increase in leakage raises the cost due to an increase in the cooling air use, which is linked to specific fuel consumption, and it can also alter gas flow paths and performance. The narrow path within the seal assembly, especially the height has the most significant affect on leakage. The height range of the narrow path studied in this paper is 0.01–0.06 mm. The behaviour of the flow passing through the narrow path has been studied using CFD modelling and measurements in a bespoke rig. The CFD and experimental results show that normalized leakage flow increases with pressure ratio before reaching a maximum. The main aim of this paper is to provide new experimental data to verify the CFD modelling for static strip seals. The typical flow characteristics validated by CFD modelling and experiments can be used to predict the flow behaviour for future static strip seal designs.

scholarly journals Performance of Volcano-Like Laser Textured Cutting Tools: An Experimental and Simulative Investigation

Lubricants ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 98 ◽  
Author(s):  
Zhengyang Kang ◽  
Yonghong Fu ◽  
Xingyu Fu ◽  
Martin Jun
Keyword(s):  
Cutting Force ◽  
Cutting Tools ◽  
Surface Texturing ◽  
Temperature Fields ◽  
Small Scale ◽  
Rake Face ◽  
Forming Process ◽  
Force Reduction ◽  
And Performance ◽  
Distribution Of Stress

In recent years, surface texturing in micro-scale has been attempted on the surface of cutting tools for multiple purposes, e.g., cutting force reduction, prolonging life-span, anti-adhesion, etc. With respect to machinability and performance, micro-groove texture (MGT) has dominated in this field compared to other textured patterns. In this study, a novel volcano-like texture (VLT) was fabricated on the rake face of cemented carbide inserts (WC-Co, YG6) by fiber laser. The following cutting experiment tested the flat, MGT and VLT tools in turning aluminum alloy 6061. The effects of coolant and cutting conditions were investigated. In addition, a validated FEM model was employed to explore the distribution of stress and temperature fields in the tool-chip interface. The initial forming process of adhesion layer on rake face was investigated as well. The results indicated that lower cutting force and less adhesion can be achieved by small scale VLT. This study not only introduced VLT on cutting tools but also revealed its comprehensive performance.

scholarly journals Alert: An Adaptive Low-Latency Event-Driven MAC Protocol for Wireless Sensor Networks

2011 ◽  
Vol 2011 ◽  
pp. 1-19
Author(s):  
Vinod Namboodiri ◽  
Abtin Keshavarzian
Keyword(s):  
Mac Protocol ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Network Applications ◽  
Alarm Systems ◽  
Minimum Latency ◽  
Multiple Sensor ◽  
Protocol Execution ◽  
And Performance ◽  
The Cost

Collection of rare but delay-critical messages from a group of sensor nodes is a key process in many wireless sensor network applications. This is particularly important for security-related applications like intrusion detection and fire alarm systems. An event sensed by multiple sensor nodes in the network can trigger many messages to be sent simultaneously. We present Alert, a MAC protocol for collecting event-triggered urgent messages from a group of sensor nodes with minimum latency and without requiring any cooperation or prescheduling among the senders or between senders and receiver during protocol execution. Alert is designed to handle multiple simultaneous messages from different nodes efficiently and reliably, minimizing the overall delay to collect all messages along with the delay to get the first message. Moreover, the ability of the network to handle a large number of simultaneous messages does not come at the cost of excessive delays when only a few messages need to be handled. We analyze Alert and evaluate its feasibility and performance with an implementation on commodity hardware. We further compare Alert with existing approaches through simulations and show the performance improvement possible through Alert.

scholarly journals ИСПОЛЬЗОВАНИЕ ТЕОРИИ НЕЧЕТКИХ МНОЖЕСТВ В ЭКОНОМИЧЕСКОМ АНАЛИЗЕ ИНВЕСТИЦИОННЫХ ПРОЕКТОВ

2018 ◽  
Vol 2 (5(17)) ◽  
pp. 44-48
Author(s):  
Файзиев Р. А. ◽  
Хаитматов У. Т. ◽  
Азаматов О. Х. ◽  
Джуманиязов Ш. Р. ◽  
Хасанова Х. Х.
Keyword(s):  
Integral Characteristic ◽  
Mathematical Methods ◽  
Investment Projects ◽  
Performance Targets ◽  
Methods Of Evaluation ◽  
Interval Approach ◽  
And Performance ◽  
The Cost ◽  
Fuzzy Interval ◽  
Theory Of Fuzzy Sets

The article outlines the main features of the use of the theory of indefinite bundles in the evaluation of the cost-effectiveness of investment projects.He analysis of methods for quantifying the effectiveness of the IP under uncertainty suggests that the existing methods either eliminate the uncertainty from the IP model, which is inappropriate, since uncertainty is an integral characteristic of any forecast, or are unable to formally describe, and take into account all possible varieties of types of uncertainty.Methods based on the theory of fuzzy sets refer to the methods of evaluation and decision-making under conditions of uncertainty. Their use implies the formalization of the initial parameters and performance targets of the IP in the form of a vector of interval values (fuzzy interval), the hit in each interval of which is characterized by a certain degree of uncertainty.Also, the fuzzy-interval approach has advantages in solving the problems of forming an optimal portfolio of investment projects. To solve the problem of forming an optimal IP portfolio, a large number of models for the formation of an optimal IP portfolio have been developed, differing from each other in the form of objective functions, variable properties, used by mathematical methods, and uncertainty.

scholarly journals Proposed Policy Preventive Maintenance Machine Moriseiki NH 4000 DCG Method Of Reliability Center Maintenance (RCM) And Risk Based Maintenance (RBM) Case Study PT. Pudak Scientific

2018 ◽  
Vol 2 (01) ◽  
Author(s):  
Fachri Husaini
Keyword(s):  
Production Capacity ◽  
Cost Of Care ◽  
Maintenance Policy ◽  
Performance Loss ◽  
Acceptance Set ◽  
Maintenance Activities ◽  
And Performance ◽  
The Cost ◽  
A Company

PT Pudak Scientific is a company engaged in the manufacture of aircraft parts industry. Meeting the precise and timely demand of aerospace parts from customers becomes a major corporate responsibility. However, Loss Revenue often occurs due to engine breakdown. So that cause because the production target is not achieved, the product reject, and the delay of delivery. One of the machines that often experience breakdown is Mori seiki NH4000 DCG. Mori seiki NH4000 DCG is the finishing machine for Blank fork End product. The demand for this part is quite large, making it a tough task for the Mori Seiki NH4000 DCG machine. But because the breakdown of the machine is high enough to cause production targets every month are often not met. In addition, Maintenance activities that have not noticed the characteristics of engine damage, as well as the distribution of historical data of the machine causing less effective and efficient actions resulted in substantial Maintenance costs. Based on the results of risk analysis of Mori Seiki NH4000 DCG engine damage, in terms of performance loss system caused by a large enough that is 3.773% of machine production capacity per year. This figure exceeds the risk acceptance criteria by the company that is 2%. Therefore it is necessary to find the appropriate Maintenance policy for the Mori Seiki NH4000 DCG machine. The approach is to use Reliability Centeres Maintenance and Risk Based Maintenance. Based on the above two approaches obtained the appropriate interval time so that the Maintenance activities more effective and can improve the efficiency of treatment by reducing the cost of care previously Rp167.506.286, - per year, to Rp 96.147.061, - per year. With the policy is expected to reduce engine breakdown and performance loss caused. So the number of risks that arise for the future are within the criteria of acceptance set by the company.

scholarly journals Application of the optimally alloyed cast irons in order to increase the durability and to ensure the cost reduction of mining and metallurgical products

2021 ◽  
Vol 303 ◽  
pp. 01005
Author(s):  
Dmitry Lubyanoi ◽  
Evgeny Pudov ◽  
Evgeny Kuzin ◽  
Olga Semenova
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
Operational Reliability ◽  
Cast Irons ◽  
Metallurgical Production ◽  
Alloyed Cast ◽  
Alloyed Cast Iron ◽  
And Performance ◽  
Working Bodies ◽  
The Cost

The article shows the relevance of the use of alloyed cast iron in mining and metallurgical engineering. The article discusses the technologies for producing naturally alloyed cast iron. For working bodies and friction units of mining machines, such as pumps, coal pumps, hydrocyclones, crushers and mills. The main type of wear for them is abrasive. To increase the wear resistance of cast iron the production of cast iron has not been sufficiently studied yet. Although the use of cast iron in a complex alloyed with manganese, silicon, chromium, titanium and vanadium has been studied. The article studies the influence of manganese, titanium and vanadium on the mechanical properties and performance of machine parts and products of mining and metallurgical production in contact with high-temperature and highly abrasive media. The rational content of titanium and vanadium in gray cast irons is established in the range of 0.05-0.1%, which ensures their heat resistance and increases their wear resistance. The content of these elements can be increased to 0.07-0.12%. Bushings made of this cast iron have the required wear resistance and can increase the operational reliability of the equipment in the conditions of mining and metallurgical production. They also replace non-ferrous metals, as well as products obtained by powder metallurgy methods.

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