Deterioration Pattern Research Articles

Predicting Structural Deterioration Condition of Individual Storm-Water Pipes Using Probabilistic Neural Networks and Multiple Logistic Regression Models

After several decades in service, the deterioration of storm-water pipe assets is inevitable. The deterioration of storm-water pipes is characterized by structural deterioration and hydraulic deterioration. Condition assessment using closed circuit television (CCTV) inspection is often carried out to assess the structural condition of pipes. However, the knowledge on the condition of storm-water pipe assets is still limited for strategic planning of maintenance and rehabilitation, because generally only a small sample is CCTV-inspected and in almost all cases, these pipes are inspected once only due to high costs. The challenge for researchers is to use the sample of CCTV-inspected pipes for developing mathematical models that can predict the structural condition of remaining pipes as well as the future condition of pipes. In this present study, the deterioration pattern of storm-water pipes is constructed on the basis that each pipe has its own deterioration rate due to its pipe factors. Based on this, two mathematical models using multiple logistic regression (MLR) and probabilistic neural networks (PNN) are developed for predicting the structural condition of individual pipes. The MLR model was calibrated using the maximum likelihood method and the PNN model was trained using a genetic algorithm (GA). The predictive performances of both models were compared using CCTV data collected for a local government authority in Melbourne, Australia. The results showed that the PNN model was more suited for modeling the structural deterioration of individual storm-water pipes than the MLR model. Furthermore, the use of GA improved the training results of the PNN model compared to the trial and error method.

Cerebral venous blood flow in growth restricted fetuses with an abnormal blood flow in the umbilical artery before 32 weeks of gestation

Objective To evaluate the brain venous circulation in fetuses with severe intrauterine growth restriction (IUGR) before 32 weeks of gestation. Study design Fifty fetuses with severe IUGR diagnosed between 27 and 32 weeks of gestation and 50 appropriate-for-gestational age (AGA) fetuses matched by gestational age were evaluated. IUGR fetuses were classified according to their hemodynamic deterioration pattern in relation to the Doppler examination of the umbilical artery (UA), middle cerebral artery (MCA) and ductus venosus (DV). The fetal venous brain blood flow was evaluated in the vein of Galen (VG), superior sagittal (SS), straight and transverse venous sinuses. Results Only the transverse sinus (TS) showed a significant reduction in the pulsatility index (PI) values in IUGR fetuses. All other veins showed similar PI values between IUGR and AGA fetuses. All cerebral veins of IUGR fetuses showed significantly increased maximum and mean velocities. All these findings did not change in relation to the hemodynamic IUGR deterioration. In nearly all normal and all IUGR fetuses, a pulsatile blood flow pattern was observed in the straight and transverse sinuses, whereas an increased pulsatile pattern in the VG and in the SS was noted in IUGR fetuses. Conclusion Brain venous blood flow in IUGR fetuses shows an increment in the maximum and mean velocities of all veins and a reduction in the PI in the transverse sinus.

Assessment of domestic water quality: case study, Beirut, Lebanon

In urban cities, the environmental services are the responsibility of the public sector, where piped water supply is the norm for urban household. Likewise, in Beirut City (capital of Lebanon) official water authorities are the main supplier of domestic water through a network of piping system that leaks in many areas. Beirut City and its suburbs are overpopulated since it is the residence of 1/3 of the Lebanese citizens. Thus, Beirut suffers deficiency in meeting its water demand. Water rationing, as a remedial action, is firmly established since four decades by the Lebanese Water Authorities. Consumers resorted then to private wells to supplement their domestic water needs. Consequently, household water quality is influenced by external factors relating to well water characteristics and internal factors depending on the types of the pipes of the distribution network and cross connections to sewer pipes. These factors could result in chemical and microbial contamination of drinking water. The objective of this study is to investigate domestic water quality variation in Beirut City emerging form the aforementioned factors. The presented work encircles a typical case study of Beirut City (Ras Beirut). Results showed deterioration pattern in domestic water quality. The predicted metal species and scales within the water pipes of distribution network depended on water pH, hardness, sulfate, chloride, and iron. The corrosion of iron pipes mainly depended on Mg hardness.

Season and activity of rheumatoid arthritis in Japan

AbstractAim: To investigate the relationship between rheumatoid arthritis (RA) activity and season.Methods: Two hundred and eighty RA patients were asked whether they experienced any deterioration at different times of year. Each patient's RA activity was also recorded on medical charts.Results: Sixty‐two percent of patients recognized seasonal deterioration. Spring and winter were common seasons of deterioration. From medical charts, there were two peaks of high deterioration. One peak was from April to June, and the other was from November to January.Conclusion: Two‐thirds of RA patients felt deterioration related to season. Evaluation and notes of the deterioration pattern could support early appropriate therapy for RA patients.

Shelf-life estimation from accelerated storage data

Traditionally, deterioration rates at elevated temperatures are extrapolated to lower ones assuming that their temperature dependence obeys the Arrhenius equation, or a similar model. For such methods to succeed, the spoilage kinetics must be known in advance and be completely defined by a single rate constant that must be independent of the food's thermal history. These assumptions may hold for certain foods and model systems, but they cannot be universally applicable. In a proposed alternative approach, no kinetics is assumed at all and it is taken for granted that the food's thermal history can and does affect the deterioration pattern. Consequently, the isothermal chemical degradation or microbial growth data are described in terms of empirical models that have the needed number of temperature dependent parameters, usually two or three. The temperature dependence of these is also described by ad hoc empirical models that are used for the extrapolation to lower temperatures. This enables the estimation of not only the ‘rate constant’ but also the whole deterioration curve. The concept is demonstrated with the degradation of vitamin C in frozen spinach and the growth of a bacterium and yeast at different temperatures. An example of lowering the salt concentration as a way of accelerating bacterial growth is also given. The quality of the predictions largely depends on the quality of the data gathered under the accelerating conditions and the proximity of these to the conditions of normal handling and storage. At least theoretically, the proposed method predictions can be extended to non-isothermal storage conditions even when the rate is a function not only of the momentary temperature but also of the food's previous thermal history. In principle, the same methodology can be used to predict quality improvement in products undergoing aging.

Silicon/graphite composites as an anode material for lithium ion batteries

Mixed silicon–graphite composites have been prepared by means of mechanical milling process. Their micro-heterogeneous structure is considered responsible for electrode failures. A fingerprint of this process is seen by cycling the carbonaceous component of the composite in an electrolyte containing small amount of propylene–carbonate (PC). Local voltage drops close to 0 V (versus Li metal) resulted in local electrode mechanical deterioration. In the presence of silicon particles such local disorders would lead to a loose interparticle contact (zones called dead spots). Deterioration pattern of the mixed composite electrode may be considered as a set of ‘dead spots’ spreading across the electrode as the cycling proceeds. Hence, a careful optimization is necessary in order to fabricate composite electrode giving minimum local disorders and having satisfactory cycling performance.

Influence of education on the pattern of cognitive deterioration in AD patients: The cognitive reserve hypothesis

The cognitive reserve hypothesis proposes that a high educational level could delay the clinical expression of Alzheimer’s disease (AD) although neuropathologic changes develop in the brain. Therefore, some studies have reported that when the clinical signs of the disease emerge, high-educated patients may decline more rapidly than low-educated patients because the neuropathology is more advanced. However, these studies have only investigated the decline of global cognition or an isolated cognitive process. To study the differential deterioration pattern of several cognitive processes according to education, the performance of 20 AD patients with a high educational level and a low educational level were compared with the performance of 20 control subjects on a neuropsychological battery. The results showed that cognitive deterioration of AD patients is different according to education, although the global performance was similar in AD patients. The high-educated patients exhibited greater impairment of abstract thinking whereas the low-educated patients showed greater impairment of memory and attentional function. This confirms that some cognitive processes, such as abstract thinking, decline more rapidly in high-educated patients whereas others seem to evolve more slowly if compared to low-educated patients. In this latter case, high-educated patients may still benefit from cognitive reserve after the diagnosis of the dementia.

The use of radiography and GIS to assess the deterioration of archaeological iron objects from a water logged environment

Abstract Pollution, acid rain, and modern agricultural practise are often blamed when archaeological metal objects are heavily deteriorated. However, looking at a deteriorated object, it can be difficult to differentiate whether the deterioration took place recently, or maybe hundreds or even thousands of years ago. A detailed knowledge of the changing environmental conditions of the archaeological site, a large number of objects, and a reliable measure for the state of preservation of the objects are necessary to assess the deterioration history. In this paper an analytical method based on X-ray radiography is used to give an objective measure for the state of preservation of iron objects. It is demonstrated that the method is robust, independent of the operator, and has good precision. With this tool and applying the use of GIS, 151 lances from a water logged environment (Nydam, Denmark) were studied, to see if it was possible to correlate the state of preservation with the exact find location, the year of excavation or the method of deposition. Apparently, in this case the method of deposition was most important, so that the deterioration pattern observed today is decided during the first few years after deposition, which took place in 200–500 AD. It has not been possible to demonstrate an increased deterioration from the first excavations in 1859 until today. The work is part of a major project in Nydam, which has also involved studying corrosion products, deterioration of modern materials, environmental parameters, and the effects of archaeological excavations.

The use of radiography and GIS to assess the deterioration of archaeological iron objects from a water logged environment

Pollution, acid rain, and modern agricultural practise are often blamed when archaeological metal objects are heavily deteriorated. However, looking at a deteriorated object, it can be difficult to differentiate whether the deterioration took place recently, or maybe hundreds or even thousands of years ago. A detailed knowledge of the changing environmental conditions of the archaeological site, a large number of objects, and a reliable measure for the state of preservation of the objects are necessary to assess the deterioration history. In this paper an analytical method based on X-ray radiography is used to give an objective measure for the state of preservation of iron objects. It is demonstrated that the method is robust, independent of the operator, and has good precision. With this tool and applying the use of GIS, 151 lances from a water logged environment (Nydam, Denmark) were studied, to see if it was possible to correlate the state of preservation with the exact find location, the year of excavation or the method of deposition. Apparently, in this case the method of deposition was most important, so that the deterioration pattern observed today is decided during the first few years after deposition, which took place in 200–500 AD. It has not been possible to demonstrate an increased deterioration from the first excavations in 1859 until today. The work is part of a major project in Nydam, which has also involved studying corrosion products, deterioration of modern materials, environmental parameters, and the effects of archaeological excavations.

Optimal lot-sizing problem with imperfect maintenance and imperfect production

In this paper, we develop an integrated model for the joint determination of both economic production quantity and level of preventive maintenance (PM) for an imperfect production process. This process has a general deterioration distribution with increasing hazard rate. The effect of PM activities on the deterioration pattern of the process is modelled using the imperfect maintenance concept. In this concept, it is assumed that after performing PM, the ageing of the system is reduced in proportion to the PM level. After a period of time in production, the process may shift to out-of-control states, either type I or type II. A minimal repair will remove the type I out-of-control state. If a type II out-of-control state occurs, the production process has to stop, and then restoration work is carried out. Examples of Weibull shock models are given to show that the use of PM reduces costs.

Forecasting Variations and Trends in Water-Main Breaks

Effective planning for the renewal of water distribution systems requires accurate quantification of the structural deterioration of water mains. Direct inspection of all water mains in a distribution system is almost always prohibitively expensive. Identifying water-main breakage patterns over time is an effective and inexpensive alternative for gauging the structural deterioration of a water distribution system. While the structural deterioration of the pipe is generally considered to be a steady, monotone process, some of the environmental and operational stresses acting upon it are time dependent, steady, or transient. These stresses result in sets of “noisy” breakage rate data that often mask the underlying deterioration (aging) patterns, especially in small data sets. If the cause of these random stresses can be identified and attributed to measurable phenomena (for example, temperatures, precipitation, and so on), a more accurate pipe deterioration pattern can be obtained. Further, better predictio...

The economic production lot-sizing problem with imperfect production processes and imperfect maintenance

This paper deals with an integrated model for the joint determination of economic production quantity and preventive maintenance (PM) level for an imperfect process having a general deterioration distribution with increasing hazard rate. The effect of PM activities on the deterioration pattern of the process is modeled using the imperfect maintenance concept. It is assumed that, after each PM, the age of the system is reduced proportional to the PM level. A numerical example is used to illustrate the effect of PM level on the cost of nonconforming items and restoration cost due to shift to the out-of-control state. It is found that performing PM will yield reductions in quality related costs. It is more economical to perform PM when the extra PM cost is compensated for by the reduction in quality related costs.

Statistical Analysis of Environmental Effects on Reliability Decay of Missiles: A Case Study

Generalized linear models are used to predict the deterioration pattern for missiles stored in four different environmental conditions. The rate of deterioration over time is assumed to be non-negative, and it is estimated from repeated measurement of the binary responses from a series of intermittent flight tests. Results of the statistical tests indicate that environmental effects are not significant on missile decay. Additionally, the estimation method for the missile shelf-life is suggested.

Microclimatic factors affecting the Trajan Column

Because of meteorological and microclimatic factors (e.g. solar radiation, gradients of temperature and moisture, air speed and turbulence) the Trajan Column is subject to deposition processes on a diurnal cycle, which alternatively increase and decrease the deposition rate of airborne pollutants. The diurnal trend of the pollutant concentration in Rome is bi-modal and the two maxima are associated with different deposition velocities, so that a simple correlation between stone deterioration and pollutant concentration averages appears to be meaningless. Field tests were carried out on the monument to investigate the diurnal and seasonal trend of factors that affect dry deposition in relation to the meteorological variables and pollution levels, i.e. phoretic forces due to temperature gradients (thermophoresis), condensation and evaporation (diffusiophoresis and Stefan flow), inertial impaction, electrostatic capture and gravitational settling. In particular, when the marble is warmer than the surrounding air, a layer of warm air rises continually along the warm part of the column, increases the upward drag of the falling particles and results in a net decrease of the gravitational settling of the coarse particles (i.e. with diameter d > 1 μm); when the marble is colder, the downward drag increases the sedimentation rate. The wind field around the monument was measured in order to investigate the diffusion potential. Turbulence generated by the shape of the column and its roughness clearly dominates the natural turbulence of the free flow. Rainwater has been recognized as being the cause of severe dissolution except in zones where whewellite is present. This is seen by comparing the deterioration pattern with the rainfall rose, and by following the run-off path which is determined by the geometry of the bas-reliefs. Dissolution is due to the chemical activity of the dry and wet depositions; it is also dependent on the physical regime of the run-off, i.e. laminar or turbulent. In the past, in addition to the physico-chemical weathering, biological deterioration occurred where meteoric water remained longer. Micrometeorological field test were carried out on the Trajan Column to investigate the diurnal and seasonal evolution of the main temperature and humidity parameters to know the microclimate of the column. Four seasonal tests have been made, each of 6 days under different weather conditions. The measurements have been made on horizontal and vertical profiles at different distances from the surface to study the heat and moisture exchanges between marble and atmosphere. The wind loads and their effects on the mechanical structure resulted in being negligible.

Neuropsychological test patterns in men for Alzheimer's and multi-infarct dementia

This paper examined three patterns of test performance on the Halstead Reitan Battery (HRB) and the Wechsler Adult Intelligence Scale-Revised (WAIS-R), including Fuld's formula, that differentiated Alzheimer's Disease (AD) from cerebrovascular disease, especially Multi-Infarct Dementia (MID). Study 1 and 2 utilized 12 AD subjects and 13 subjects who had transient ischemic attacks (TIAs). All of the subjects in this study were male. The severity of impairment was equated. A WAIS-R deterioration pattern was found for the AD subjects, from which a formula was derived that correctly identified 84% of the subjects. The Fuld formula identified 76%. In regard to the HRB, Motor tests especially were less impaired for AD subjects and the HRB formulas correctly identified about 92% of the subjects. A third study, using an entirely new sample, applied these formulas to 11 AD and 28 MID subjects. The same rate of separation for the HRB formulas was found. Neither the WAIS formula, with the original cutting points, nor did the Fuld formula quite reach significance.

Operational safety of hoisting ropes

The present paper describes a method for determining the operational safety of hoisting ropes. The method depends on the relationship between the actual breaking strength of a rope in service and the load the rope is subjected to. The actual breaking strength of a rope is determined with the use of an electromagnetic defectograph and is based on the known rope deterioration pattern. The latter is defined in laboratory tests on the same rope construction. To illustrate an application of this method, the present paper also describes the laboratory tests conducted to define the pattern of wear progress for the selected ropes as well as the results of rope-loud measurement on a multi-rope friction hoist.

Occupational asthma in a factory with a contaminated humidifier.

Thirty five printers who had work related wheeze, chest tightness, or breathlessness kept two hourly records of their peak expiratory flow for at least two weeks. They all worked in a factory supplied by air from contaminated humidifiers. The peak flow records showed consistent work related deterioration in 15 workers, nine of whom had a diurnal variation in peak flow exceeding 20%. Ten workers kept further records after the humidifiers had been cleaned, other work practices remaining unchanged. There was substantial improvement in all 10 workers, implying that material from the contaminated humidifier was the cause of the work related changes in peak flow. The patterns of work related changes in peak flow fell into four groups: falls maximal on the first work day, falls maximal midweek, falls equivalent each work day, and falls progressive throughout the working week. Three quarters of this last group had immediate prick test responses to humidifier antigen, which were negative in all the others with work related changes in peak flow. This suggests that the progressive daily deterioration pattern alone is due to an IgE mediated response to humidifier antigens. A large range of microorganisms was identified in the humidifiers. No single microorganism appeared to be the antigen responsible for the precipitating antibody seen in 75% of the study population.

Erythrocyte agglomeration and survival studies in citrate-phosphate-dextrose (CPD) units.

We have previously reported increased tendency to agglomeration in CPD-stored erythrocytes. In the present study we investigated the deterioration pattern of fresh units, as detected by agglomeration, free hemoglobin levels, ATP levels, osmotic fragility, and certain enzymatic activities. When the negative test was converted to a positive one, the 24-h survival values of these units were determined by autotransfusion. A positive agglomeration occurred while viability was still above 70%. Fresh units had high ATP levels and negative agglomeration while old units had low ATP levels and positive agglomeration. However, in intermediate-storage units, no definite correlation between ATP and agglomeration was found. Agglomeration seems to reflect the degree of changes in stored erythrocytes. However, further studies are needed before this test may serve for prediction of post-transfusion viability.