A new warranty policy for heterogeneous items subject to monotone degradation processes

2021 ◽  
pp. 1748006X2110287
Author(s):  
Ji Hwan Cha ◽  
Maxim Finkelstein
Keyword(s):  
Degradation Process ◽  
Optimal Time ◽  
Cost Analyses ◽  
Heterogeneous Populations ◽  
Penalty Cost ◽  
Degradation Processes ◽  
Sudden Failure ◽  
Predetermined Level

A new renewable warranty policy is suggested that increases the probability of its success and can decrease the corresponding costs for certain ranges of parameters. It deals with heterogeneous populations of items from two subpopulations (‘weak’ and ‘strong’) and is aimed at elimination and further replacement of weak items after screening at some optimal time. This elimination is performed when degradation described by the corresponding mixed degradation process reaches some optimally predetermined level. Probabilistic and cost analyses of the model are performed and the illustrative example is presented. It is shown that the proposed warranty policy with inspection outperforms the conventional one in a probabilistic sense. Furthermore, the proposed policy becomes economically beneficial especially when the additional penalty cost caused by a sudden failure is large.

Distribution of Acidity and Alkalinity on Degraded Manuscripts Containing Iron Gall Ink

2015 ◽  
Vol 36 (3) ◽  
Author(s):  
Eva Marín ◽  
Maria Carme Sistach ◽  
Jessica Jiménez ◽  
Miguel Clemente ◽  
Guillem Garcia ◽  
...  
Keyword(s):  
Good Condition ◽  
Degradation Process ◽  
Degradation Processes ◽  
Alkaline Reserve ◽  
Hydrolysis Of Cellulose ◽  
Relevant Variables ◽  
Long Time ◽  
Iron Gall ◽  
The Stability

AbstractLong-time preservation of manuscripts depends on the stability of their support. One of the most important degradation processes of paper manuscripts containing iron gall ink is the acid hydrolysis of cellulose. The heterogeneity of the distribution of their constituent materials, together with the defined position of ink as a source of degradation agents, makes it difficult to obtain reliable and detailed information about degradation processes. The aim of this study is to contribute to the knowledge of the acid degradation process by looking at the distribution of relevant variables (pH, acidity and alkaline reserve) on real untreated iron gall ink containing manuscripts at different degradation stages. The study discusses the well-known differences between surface and cold extraction pH determination. It corroborates the relationship between pH, acidity and alkalinity and degradation stages, pointing out that acidity values for some manuscripts in apparent good condition are not far from those obtained for degraded manuscripts. The results indicate that in some partially degraded manuscripts, the coexistence of acid areas and areas with an alkaline reserve which do not participate in the neutralization process is possible. The role of water as a solvent for this equilibrium has also been evaluated.

Organic matter content controls the N and P degradation process on biogeochemical interfaces: A micro-ecosystem scale study based on SoilChips-XPS-Zymography integrated technique in paddy soils

2020 ◽  
Author(s):  
Liang Wei
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Photoelectron Spectroscopy ◽  
Organic Matter Content ◽  
Degradation Process ◽  
Matter Content ◽  
Microbial Production ◽  
Paddy Soils ◽  
Rrna Gene ◽  
Degradation Processes

<p>The biogeochemical interfaces are hotspots for organic matter (OM) transformation. However, direct and continuouxiacis tracing of OM transformations and N and P degradation processes are lacking due to the heterogeneous and opaque nature of soil microenvironment. To investigate these processes, a new soil microarray technology (SoilChips) was developed and used. Homogeneous 2-mm-diameter SoilChips were constructed by depositing a dispersed paddy soils with high and low soil organic carbon (SOC) content. A horizon suspension on a patterned glass. Dissolved organic matter from the original soil was added on the SoilChips to mimic biogeochemical processes on interfaces. The chemical composition of biogeochemical interfaces were evaluated via X-ray photoelectron spectroscopy (XPS) and the two-dimensional distribution of enzyme activities in SoilChips were evaluated by zymography. Over 30 days, soil with high SOC content increases microbial nutrition (N and P) requirements than soil with low SOC evidenced by higher hotspots of β-1,4-N-acetaminophen glucosidase, and acid phosphomonoesterases and higher 16S rRNA gene copies. The degree of humification in dissolved organic matter (DOM) was higher and the bioavailability of DOM was poorer in soil with high SOC than soil with low SOC. The poorest bioavailability of DOM was detected at the end of incubation in soil with high SOC. Molecular modeling of OM composition showed that low SOC mainly facilitated the microbial production of glucans but high SOC mainly facilitated the microbial production of proteins. We demonstrated that SOC content or DOM availability for microorganisms modifies the specific OM molecular processing and N and P degradation processes, thereby providing a direct insight into biogeochemical transformation of OM at micro-scale.</p>

scholarly journals Reliability Modeling for Systems with Multiple Degradation Processes Using Inverse Gaussian Process and Copulas

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Zhenyu Liu ◽  
Xiaobing Ma ◽  
Jun Yang ◽  
Yu Zhao
Keyword(s):  
Degradation Process ◽  
Reliability Estimation ◽  
Scale Transformation ◽  
Distribution Model ◽  
Inverse Gaussian ◽  
Random Drift ◽  
Reliability Modeling ◽  
Degradation Processes ◽  
Inverse Gaussian Process ◽  
Comparison Results

We develop a reliability model for systems with s-dependent degradation processes using copulas. The proposed model accommodates assumptions of s-dependence among degradation processes and allows for different marginal distributions. This flexibility makes the model more attractive compared with the multivariate distribution model, which lay on the limitation of the homogeneous marginal distribution and can only describe linear correlation. Marginal degradation process is modeled by the inverse Gaussian (IG) process with time scale transformation. Furthermore, we incorporate random drift to account for the possible heterogeneity in population. This paper also develops the statistical inference method using EM algorithm with two-stage procedure. The comparison results of the reliability estimation under both s-dependent and s-independent assumptions are illustrated in the illustrative example to demonstrate the applicability of the proposed method.

scholarly journals A hybrid approach for modelling multidimensional degradation processes

2021 ◽  
Vol 1207 (1) ◽  
pp. 012023
Author(s):  
Renyan Jiang ◽  
Binbin Xiong
Keyword(s):  
Model Selection ◽  
Residual Life ◽  
Hybrid Approach ◽  
Degradation Process ◽  
Closed Form Expression ◽  
Second Phase ◽  
Two Phase ◽  
Degradation Model ◽  
One Dimensional ◽  
Degradation Processes

Abstract Degradation processes are often multidimensional. Modeling such degradation processes needs to address two key issues: indicator fusion and degradation model selection; and they have been separately addressed in the literature. This paper proposes a hybrid approach to jointly address these two issues. The proposed approach first fuses multiple degradation indicators into a composite degradation indicator. This fusion step involves data normalization, aggregation model selection and determination of indicator weights. After the fusion step, the problem becomes one-dimensional, and the existing method to select the degradation model for a one-dimensional degradation process can be applied. The resulting model obtained from the proposed approach can be a two-phase model; and the model for the second phase has a closed-form expression. This considerably facilitates residual life prediction. A real-world example is included to illustrate the proposed approach and its appropriateness.

Degradation Assessment for Machinery Prognostics Using Hidden Markov Models

2005 ◽  
Author(s):  
Hai Qiu ◽  
Haitao Liao ◽  
Jay Lee
Keyword(s):  
Hidden Markov Models ◽  
Prior Knowledge ◽  
Probabilistic Models ◽  
Markov Models ◽  
Hidden Markov ◽  
Degradation Process ◽  
Full Understanding ◽  
Degradation Processes ◽  
Degradation Pattern ◽  
Detection And Recognition

Degradation detection and recognition of degradation pattern are crucial to the successful deployment of prognostics. A machine degradation process is known to be stochastic instead of deterministic. Recognizing the degradation pattern needs helps from stochastic and probabilistic models. Among various stochastic approaches. Hidden Markov Models (HMMs) have been proven to be very effective in modeling both dynamic and static signals [1]. In this paper, aiming to providing a guideline of how to effectively and efficiently use the HMMs to assess degradation for various machinery prognostic applications, three different approaches of applying the HMMs are reviewed and compared. It demonstrates that depending on the varieties of applications, available prior knowledge, and characteristics of degradation processes, those three implementation approaches perform differently. A full understanding of the strengths and weaknesses of each deployment approach is extremely important in order to effectively utilize this powerful tool for system degradation assessment.

Bayesian degradation modelling for spare parts inventory management

2020 ◽  
Vol 32 (1) ◽  
pp. 31-49 ◽  
Author(s):  
Cesar Ruiz ◽  
Edward Pohl ◽  
Haitao Liao
Keyword(s):  
Inventory Management ◽  
Optimal Solution ◽  
Planning Horizon ◽  
Degradation Process ◽  
Spare Parts ◽  
Optimal Time ◽  
Model Parameters ◽  
Stochastic Dynamic ◽  
Spare Parts Management ◽  
Spare Parts Inventory

Abstract Decision makers in various sectors, such as manufacturing and transportation, strive to minimize downtime costs. Often, brief-planned stoppage times allow for changes in shifts and line configurations and longer periods are scheduled for major repairs. It is quite important to proactively make use of these downtimes to reduce the costs of unexpected downtimes due to failures. Among many aspects, the availability of spare parts significantly affects the operational costs of such systems. Current sensor technologies enable the condition monitoring of critical components and degradation-based spare parts management. This paper focuses on Bayesian degradation modelling for spare parts inventory management for a new system. We propose a stochastic dynamic program to minimize the expected spare parts inventory cost for a fixed planning horizon. A numerical example illustrates the value of Bayesian analysis in this management setting. The proposed methodology finds the optimal time between long stoppages and optimal spare parts order quantity when the prior information about the degradation process is accurate. The methodology can be used to analyse the sensitivity of the optimal solution to changes in the accuracy and bias of the prior distributions of the model parameters, the cost structure and the number of machines in the system.

scholarly journals Degradation processes in the soils of the Kolodnytsia River basin

2017 ◽  
pp. 193-203
Author(s):  
Nadiya Lemega
Keyword(s):  
River Basin ◽  
Soil Degradation ◽  
Arable Land ◽  
Morphological Characteristics ◽  
Vegetation Period ◽  
Degradation Process ◽  
Soil Mass ◽  
Water Erosion ◽  
Genetic Profile ◽  
Degradation Processes

This article presents the results of soil degradation studies of the Kolodnytsia River basin. The basin approach is applied in soil-geographical studies. The conditions for the formation of soils are studied depending on the morphometric characteristics of the river basin and soil-bearing rocks. The analysis of the causes of the spread of degradation processes of various species, which cause soil degradation, is carried out. Particular attention is paid to the anthropogenic factor of soil degradation, which began with the development of the territory by white Croats, that is, more than a thousand years ago. To study the degradation processes in the soils of the basin of the Kolodnytsia River, the following methods were used: comparative-geographic, comparative-profile, analytical, statistical, cartographic, basin, and catena. Field studies were conducted in the after-vegetation period. Soil erosion is the most widespread degradation process in the basin of the Kolodnytsia River, which is characterized by the destruction of the soil cover, the removal, transfer and redeposition of the soil mass. Over the past decades, erosion degradation has accelerated and taken on greater dimensions. Erosion degradation caused a decrease in the thickness of the genetic profile of soils, in weakly eroded varieties by 20 cm, in moderately eroded ones by 44 cm. In cultivated soils, the structural and aggregate state deteriorates. The content of agronomically valuable aggregates in the size of 10-0.25 mm in the humus-eluvial horizon of NOT soil under the forest is 52.6 %, under arable land – 25.3 %. The structural and aggregate composition of soils is characterized as satisfactory, the structural ratio is 1.10. Water erosion not only leads to a change in the morphological characteristics and physical properties of the soil, but also to loss of humus in the soil, nitrogen, phosphorus and other nutrients, a decrease in fertility and the like. To reduce soil degradation, it is necessary to minimize soil loading, improve the humus condition, and conserve moderately eroded soil. Key words: podzolic-soddy soils, degradation processes, water erosion, land conservation.

scholarly journals Soil degradation in Volyn region: current state, dynamics, ways of reduction

2021 ◽  
Vol 30 (2) ◽  
pp. 239-249
Author(s):  
Vasyl O. Fesyuk ◽  
Iryna A. Moroz ◽  
Ruslan V. Kirchuk ◽  
Serhii V. Polianskyi ◽  
Mykola A. Fedoniuk
Keyword(s):  
Agricultural Land ◽  
Degradation Process ◽  
Land Conservation ◽  
Vegetative Cover ◽  
Main Aspect ◽  
Protective Measures ◽  
Degradation Processes ◽  
Current State ◽  
Arable Farming ◽  
High Level

Recently, the problem of decrease in soil fertility has become more serious, pos- ing a threat to food safety of the country. The main cause is violation of technologies of rational arable farming, which leads to deterioration of the qualitative condition of soils, their degradation. Therefore, development of protective measures for soils against degradation processes is a relevant problem nowadays, solving which would preserve soils and improve their condition. The article evaluates the current condition of degradation of soils in Volyn Oblast. We determined the main aspect of degradation processes, their scales and territorial distribution. We determined that in the structure of the land fund of the Oblast, 52% is occupied by agricultural land, indicating high level of agrarian cultivation of lands. For the last 15 years, the structure of the land fund of Volyn Oblast had undergone insignificant changes, and the most of the area of the land remains unaltered. The area of agricultural lands has somewhat decreased, whereas the area of forests and forest-covered territory has increased. The area of open lands with no vegetative cover has decreased by 0.15%. Ploughed fields in the southern districts of Volyn Oblast exceed the allowable limits, accounting for over 60%. We analyzed the dynamics of the degradation process of soils in the Oblast. We determined that the degradation of soils was to the greatest degree caused by manifestations of erosion and deflation. Water erosion manifested in the territory of Volodymyr-Volynskyi, Ivanychi, Lokachi, Horohiv, Lutsk and Kivertsi districts. Deflatable soils in the Oblast account for 258.2 thousand ha, most of which are in Kovel, Turiisk, Rozhyshche, Stara Vyzhivka districts. Measures for improving low-productive lands, and also land conservation, are being implemented in the Oblast. However, their scale is insufficient. We propose a complex of measures for protecting soils and preventing their degradation.

The Research on Degradation Failure Life and Degradation Data Structure

2013 ◽  
Vol 710 ◽  
pp. 294-297
Author(s):  
Yi Dong Wang ◽  
Yi Zhou He ◽  
Hai Bo Liu ◽  
Jun Wei Lei
Keyword(s):  
Distribution Function ◽  
Cumulative Distribution Function ◽  
Reliability Assessment ◽  
Degradation Process ◽  
Cumulative Distribution ◽  
Degradation Data ◽  
Sudden Failure ◽  
Degradation Failure ◽  
Degradation Degree ◽  
Failure Life

In order to solve the reliability assessment in the case of competition failure induced by the coexistence between burst-type failure and degradation-type failure in the product, the method of degradation amount distribution was adopted to describe the degradation process of performance in product. Considering the relativity between sudden failure and degradation degree, the cumulative distribution function of sudden failure was calculated from the standpoint of degradation amount. Eliminating the affect of sudden failure according to a certain conditional probability in the degradation amount distribution function, which helps to realize reliability assessment based on competitive failure analysis.

scholarly journals Optimization modeling of degradation processes in crude oil spilled on the sea surface considering the wind conditions

2020 ◽  
Vol 4 (2) ◽  
pp. 150-153
Author(s):  
Hikmat G. Asadov ◽  
◽  
R. S. Mammadli ◽  
Keyword(s):  
Wind Speed ◽  
Crude Oil ◽  
Time Dependence ◽  
Optimization Model ◽  
Degradation Process ◽  
Sea Surface ◽  
Oil Degradation ◽  
Optimization Modeling ◽  
Degradation Processes ◽  
Model Study

The article describes an optimization model study of degradation processes in crude oil spilled on the sea surface considering the wind conditions. A new configuration of a simplified optimization model of the oil degradation process on the sea surface is proposed. Based on the proposed configuration, a simplified optimization model of oil degradation on the sea surface has been developed. The optimal relationship between the time dependence of the wind speed and the fractional volume of oil volatilization is established, at which the minimum fractional volume of oil dissolved in water is attained.

Sign in / Sign up

Export Citation Format

Share Document