Effect of log loading on the performance of wood room

2014 ◽  
Vol 29 (2) ◽  
pp. 201-210
Author(s):  
Ari Isokangas ◽  
Kari Ala-Kaila ◽  
Markku Ohenoja ◽  
Aki Sorsa ◽  
Kauko Leiviskä
Keyword(s):  
Product Quality ◽  
Material Properties ◽  
Raw Material ◽  
Performance Criteria ◽  
Processing Unit ◽  
Level Control ◽  
Paper Mills ◽  
Remarkable Effect ◽  
Loading Process ◽  
Small Wood

Abstract The purpose of this paper is to analyse the log loading process of wood room, which is typically the first processing unit in pulp and paper mills. The aim is to improve the log loading process to obtain production with a constant log flow of well de-iced logs to the debarking drum. This way it is possible to reduce costs and enhance product quality. The research was carried out utilising a log loading simulator. The parameters of the simulation model were selected on the basis of process observations on a mill. The results indicate that it is essential to adjust the process and equipment parameters, raw material properties and truck loader operation together in order to reach the target capacity with minimum costs. Especially the speed of the infeed conveyor affects all performance criteria and should be selected carefully. In addition, wood yard logistics and raw material properties have a remarkable effect on the wood room performance. The results can be utilised in mills to allow the upper level control perform in a planned way so that small wood loss and good product quality can be obtained.

Material Properties and Design Aspects of Folding Bicycle Frame

2011 ◽  
Vol 264-265 ◽  
pp. 777-782 ◽  
Author(s):  
M.A. Maleque ◽  
M.S. Hossain ◽  
S. Dyuti
Keyword(s):  
Material Properties ◽  
Raw Material ◽  
New Materials ◽  
Materials Properties ◽  
Advantages And Disadvantages ◽  
Bicycle Frame ◽  
Successful Design ◽  
Future Direction ◽  
The Relationship ◽  
Comprehensive Study

successful design of folding bicycle should take into account the function, material properties, and fabrication process. There are some other factors that should be considered in anticipating the behavior of materials for folding bicycle. In order to understand the relationship between material properties and design of a folding bicycle and also for the future direction in new materials with new design, a comprehensive study on the design under different conditions are essential. Therefore, a systematic study on the relationship between material properties and design for folding bicycle has been performed. The advantages and disadvantages matrix between conventional bicycle and folding bicycle is presented for better understanding of the materials properties and design. It was found that the materials properties of the folding bicycle frame such as fatigue and tensile strength are the important properties for the better performance of the frame. The relationship between materials properties and design is not straight forward because the behavior of the material in the finished product could be different from that of the raw material. The swing hinge technique could be a better technique in the design for the folding bicycle frame.

scholarly journals Safety margin against the fatigue fracture under random loading

2018 ◽  
Vol 165 ◽  
pp. 22033 ◽  
Author(s):  
Martin Garan ◽  
Vladimír Chmelko ◽  
Ervin Schafer
Keyword(s):  
Yield Stress ◽  
Fatigue Fracture ◽  
Cross Section ◽  
Material Properties ◽  
Safety Margin ◽  
Time Varying ◽  
Random Loading ◽  
Fatigue Lifetime ◽  
Loading Process

The fatigue lifetime of the structure in operation is express in the number of working cycles, kilometers or time depending units. By harmonic process of loading is possible to express the safety margin as reserve against the required lifetime in the form of number cycles or amplitude of loading. By nonharmonic character of loading process in operation is difficult to express the level of safety margin as the reserve of loading (safety margin in loading). On the case of towing trailer will be discussed more ways of expression the reserve (safety margin) of structure against the fatigue fracture for required fatigue lifetime. For experimental acquired loading process in the most loaded cross-section will be discussed concept of determination of the level safety as reserve in the form of loading parameters. In the case, when the peaks of loading process exceeding the material yield stress (in the most loaded point of the structure) will be discussed concept of expression of loading in the form of time-varying process of strain. By using the cyclic material properties obtained in mode with controlled total strain is possible the safety margin to express also as the multiple of process loading parameters.

Mechanism of High Temperature Embrittlement and Loss of Corrosion Resistance in AISI Type 446 Stainless Steel

CORROSION ◽  
1971 ◽  
Vol 27 (12) ◽  
pp. 531-544 ◽  
Author(s):  
J. J. DEMO
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Material Properties ◽  
Chromium Content ◽  
Raw Material ◽  
Construction Work ◽  
Ferritic Alloys ◽  
High Chromium ◽  
Aisi Type ◽  
Resistance To Stress

Abstract The ferritic alloys, particularly AISI Type 446 steel with its high chromium content, have desirable properties of corrosion resistance, low raw material cost, and resistance to stress corrosion cracking (SCC); yet they are not widely used in construction work because of the damaging effects of high temperature exposures (such as welding) on their corrosion resistance and ductility. This work describes the causes for their loss of corrosion resistance and ductility, and defines changes in composition and heat treatment that would improve their material properties.

Quantitative Selection of Variation Reduction Plans

2000 ◽  
Vol 122 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Anna C. Thornton
Keyword(s):  
Product Quality ◽  
Performance Criteria ◽  
Performance Requirement ◽  
Variation Reduction ◽  
Variation Propagation ◽  
Design And Manufacturing ◽  
Optimal Resource ◽  
Multiple Product ◽  
Reduction Costs ◽  
Selection Of

Quality has been a rallying call in design and manufacturing for the last two decades. One way to improve quality is through variation reduction (VR). VR teams use tools such as Design of Experiments (DoE) and robust design to improve product performance and quality by reducing variation introduced by manufacturing processes. Because VR teams are typically resource constrained, they must carefully select where to focus their efforts. Planning for VR is complex because reduction efforts are executed on individual features and processes but benefits are accrued when the overall product quality improves. The problem is further complicated by the existence of multiple performance criteria and hundreds of processes and dimensions that effect each performance requirement. Consequently, VR teams typically use qualitative assessments to prioritize and schedule their efforts. This paper provides a mathematical model capable of optimally allocating VR resources for a complex product. The VR model has three parts: a model of variation propagation, a model of variation costs, and a model of variation reduction costs. These models are used to directly calculate the optimal resource allocation plan and schedule for a product with multiple product quality requirements. An example from the aerospace industry is used to demonstrate the theory. [S1050-0472(00)00602-4]

Comparative evaluation of critical operating conditions for a tubular catalytic reactor using thermal sensitivity and loss-of-stability criteria

2010 ◽  
Vol 64 (4) ◽  
Author(s):  
Gheorghe Maria ◽  
Dragoş-Nicolae Ştefan
Keyword(s):  
Thermal Sensitivity ◽  
Fixed Bed ◽  
Optimal Operation ◽  
Operating Conditions ◽  
Raw Material ◽  
System Stability ◽  
Performance Criteria ◽  
Matrix Analysis ◽  
Critical Conditions ◽  
Catalytic Reactor

AbstractOptimal operation of a chemical reactor according to various performance criteria often drives the system towards critical boundaries. Thus, precise evaluation of runaway limits in the parametric space becomes a crucial problem not only for the reactor’s safe operation, but also for over-designing the system. However, obtaining an accurate estimate for operating limits is a difficult task due to the limited validity of kinetic models describing complex processes, as well as the inherent fluctuations of the system’s properties (catalyst, raw-material quality). This paper presents a comparison of several effective methods of deriving critical conditions for the case of a tubular fixed-bed catalytic reactor used for aniline production in the vapour phase. Even though the methods being compared are related to one another, the generalised sensitivity criterion of Morbidelli-Varma (MV) seems to be more robust, not depending on a particular parameter being perturbed, when compared to the criteria that detect an incipient loss of system stability in the critical region (i.e., div-methods based on the system’s Jacobian and Green’s function matrix analysis). Combined application of div- and MV criteria allows for an accurate evaluation of the distance from the reactor’s nominal conditions to the safety limits.

Pressureless Sintering the Al2O3/SiC Nanocomposites in Deoxidized Atmosphere

2007 ◽  
Vol 280-283 ◽  
pp. 1093-1096 ◽  
Author(s):  
Zhen Zhen Peng ◽  
Shu Cai ◽  
Yan Wei Wang ◽  
Hou Zheng Wu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Surface Investigation ◽  
Material Properties ◽  
Ceramic Matrix ◽  
Raw Material ◽  
Pressureless Sintering ◽  
Dispersion Phase ◽  
Temperature Fracture ◽  
General Material

Many significant improvements have been shown in mechanical properties of ceramic nanocomposites with ceramic matrix being dispersed with second sub-micro sized (or nano-sized) phase. This study designed and fabricated Al2O3/SiC nanocomposites with a raw material used for 85% alumina as matrix and SiC grits in submicro-scale as dispersion phase via a controlled pressureless sintering in air. With coarse SiC powder as bed powder, both C and SiC powder making deoxidized atmosphere, 85Al2O3/SiC nanocomposites with different SiC contents were densified by pressureless sintering at low temperature. Fracture surface investigation indicated that dense nanocomposites with small grain size were produced. General material properties and microstructure were measured and characterized. The results showed that composites sintered in deoxidized atmosphere had better mechanical properties than those sintered in flowing argon.

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