Cabinet Test Research Articles

Comparative study between natural and artificial weathering of acrylic‐coated steel, aluminum, and galvanized steel

AbstractSince testing organic coatings under natural conditions is a time‐consuming process, accelerated methods are needed to produce results in less time. A simulated environment cannot fully reproduce actual operating conditions, so it is important to investigate the correlation between accelerated and natural aging test results. In this article, the natural aging of painted steel, aluminum, and hot‐dip galvanized steel is studied for 1 year under continental climate conditions. The environmental parameters responsible for the change of the protective system in a continental urban environment were monitored: time of wetness, ultraviolet radiation, and temperature. The extent of deterioration is compared with similar samples weathered by accelerated testing using electrochemical impedance spectroscopy, differential scanning calorimetry, and gloss measurements. Neutral salt spray chamber, prohesion test, immersion in a quiescent salt solution, and ultraviolet B‐rays (UVB) exposure test are considered. The results of the accelerated cabinet tests are discussed, and the effect is evaluated for the various coated metals. This study highlights the major problems encountered in building a model to predict durability in such a critical area as the durability of organic coatings for metal structures.

Low viscosity protective oil for temporary protection of metal components against corrosion

Corrosion of metals is the gradual destruction of metal under the impact of environmental factors. Chemical or electrochemical processes on the surface of the metal cause irreversible changes in the structure of the metal. To prevent this, during storage or transport, the surfaces of metal elements must be protected against environmental factors, which include: high air humidity, acid rain and variable temperature. These factors accelerate the corrosion process, which cannot be eliminated, but can be reduced by protecting metal elements with e.g. protective oils. Some metals have the ability to passivate, which is a natural protective agent that prevents corrosion. It consists in the formation of an oxide of this metal on the metal surface. Where there is no natural protection against corrosion, protective measures must be used. This paper presents the technology for the production of protective oil for temporary protection against corrosion. The innovation of this project is that the oil will form a thin, well adhering protective layer on the metal surface, which can be easily removed. It is characterised by very low viscosity and low dripping time. It is possible to achieve by using proper base oil with carefully selected anti-corrosion additives. Based on the standard PN-75/C-04154 Petroleum products. Rust protection by metal preservatives the humidity cabinet test method, corrosion tests were carried out. The paper presents the results of a humidity cabinet test for an oil mixture based on deeply refined base oil and properly selected refining additives. The test results confirmed very good anti-corrosive properties of the developed oil due to the use of a corrosion inhibitor and an oxidation inhibitor. The thickness of the protective layer formed on the metal surface was calculated based on a mathematical formula. The resulting layer forms a thin oil film, easy to remove and protecting the metal surface from corrosion.

Pushing the Boundaries of Conversion Coatings with an Unconventional Approach

In the 20th century, the use of steel as the primary construction material for applications such as vehicles, bridges, and buildings led to the development of surface protection by phosphate based conversion coatings. The discovery of anti-corrosion property of phosphatized surfaces can be dated back to 1906 when iron and steel were phosphatized using a phosphoric acid solution. Over time, numerous technical enhancements were achieved in the performance of phosphate coatings such as reduction in process time and temperature and the use of oxidizing agents such as nitrates for accelerated kinetics. However, zinc phosphate is not a universally suitable system; with the current market growth of aluminum alloys and their suitability for lightweight applications, automotive industries are utilizing aluminum alloys (e.g. AA6022) to reduce the vehicle weight to improve fuel efficiency. Interestingly, running aluminum alloys in zinc phosphate baths leads to excessive sludge formation and faster depletion of pretreatment bath. The frequent bath replenishments, increased sludge disposal costs, and new environmental constraints on the usage of phosphorous, nitrates, and nickel compounds in the pretreatment solution, drive the investigation of new technologies based on titanium and zirconium compounds. Zirconium and titanium based coatings offer several advantages over conventional zinc phosphate coatings, e.g. a very thin film thickness (~100 nm), a simpler process, and an environmentally friendly pretreatment solution.During the formation of conversion coatings, the very top surface of metal alloys undergoes an oxidation reaction (e.g. M → Mn+ + ne‒). This reaction is coupled with the reduction of hydrogen ion in the pretreatment bath (e.g. H+ + e‒ → ½ H2) which leads to a slightly higher pH in the vicinity of metal substrate. If adjusted to suitable conditions, the passivating species are hydrolyzed on the substrate and determines the corrosion and adhesion properties of the alloy surface. The research at PPG Industries focuses on tuning the chemistry of pretreatment solutions, chemical modifications of subsequent layers, and engineering processing conditions which can favor the thermodynamic stability and kinetic growth of coating systems. Besides that, the utility of several analytical tools such as SEM, XPS, XRF and various modes of corrosion testing – cabinet tests, electrochemical tests, and immersion tests – are instrumental in the ongoing research. This presentation will focus on the historical development of conversion coatings, shortcomings in the phosphatized surfaces, processing and mechanism of thin film coatings, and ongoing research at PPG Industries.

Electronic component cooling inside switch cabinets: combined radiation and natural convection heat transfer

The thermal conditions inside switch cabinets for industrial applications without cooling devices are equally influenced by natural convection and radiation heat transfer. In this work the open source library OpenFOAM is applied and enhanced, in order to simulate the temperature field of the air inside the cabinet. Turbulent natural convection heat transfer is modeled using Menter’s SST model. Radiation heat transfer is modeled using a surface-to-surface model, whereas the view factors are computed based on a Monte Carlo algorithm. Numerical results obtained with different flow models are compared with measurements and correlations from literature for a cavity and a Rayleigh-Benard test case. The Radiation model is validated against comparative numerical data. Finally, the models are applied to calculate the temperature field of a switch cabinet test rig. These numerical results are compared with experimental data.

Effect of Partial Cladding Pattern of Aluminum 7075 T651 on Corrosion and Mechanical Properties

The corrosion resistance of aluminum 7075 T651 in full clad (Alclad), partial clad, and bare (unclad) forms was compared after 300 hours of corrosion exposure in an acidic salt spray cabinet test at 36°C. After corrosion exposure, severe to moderate exfoliation corrosion was observed on the unprotected medium sized test panel, light general corrosion was observed on the partially clad panel, and patches of corrosion not penetrating the clad layer were observed on the fully clad panel. After corrosion tests, the tensile strength of partially clad, fully clad, and unprotected panels decreased by 3.4%, 4.0%, and 5.3%, respectively.

Experimental investigation on electroplastic effect of DP980 advanced high strength steel

This paper investigated the influence of the electric pulses on the flow behavior and plasticity of the advanced high strength steel (AHSS) Dual Phase, DP980. In order to isolate the thermal effect of the electric pulses, two kinds of uniaxial tensile tests at the same testing temperature were carried out: (1) isothermal tensile test carried out in an environment cabinet and (2) electrically-assisted isothermal tensile test. The stress–strain curves were recorded and compared. The results indicate that at the same testing temperature, the stress–strain curves obtained by test (1) are generally lower than curves deserved by test (2). It demonstrates that electric pulses can not reduce the flow stress when compared with the case that without electric pulse which is contrary to the traditional electroplastic effect. Another result is that when the testing temperature is not more than 573K, the stress–strain curves obtained by both tests are higher than the tension curve in room temperature and the cases are opposite when testing temperature is more than 573K. In addition, the elongation improvement is not observed as well in the stress–strain curves. The difference between the two tests when compared the cross section shrinkage rate and the fracture elongation rate is not obvious. From another aspect to study the athermal effect of the electric pulse, tests with only varying the peak current density or pulse frequency at the same testing temperature were conducted. The results once again show that no evident difference between the stress–strain curves. It confirms that no athermal effect exists in DP980. However, with temperature elevated to 473K, the material is strengthened and then weakened as temperature exceeds 473K. Scanning electron microscope (SEM) analysis was adopted to better understand the observed phenomena. The results show that the decomposion of the martensite and the thermal effect are the main reason that attributes to the strength variation. Fracture surface morphology analysis indicates that the appearance of the shallower and smaller dimples as well as fracture platform represents the bad plasticity when increasing temperature. Meanwhile, fracture pattern is transformed from brittle fracture in test (1) to ductile fracture in test (2) when tensioned at 673K.

Prevalencia de alteraciones gastrointestinales en adultos con inmunodeficiencia común variable en el Hospital de Especialidades Dr. Bernardo Sepúlveda

The common variable immunodeficiency (CVID) shows a variable incidence, from 1:15,000 to 1:117,000, without gender predominance. The incidence of gastrointestinal manifestations in these patients ranges from 20-60%, and these may be the first and only clinical manifestation of CVID, while other patients develop gastrointestinal complications during the course of it. In Mexico there is little information regarding the type and frequency of gastrointestinal disorders presented by adult patients with CVID. To determine the prevalence of gastrointestinal manifestations in adult patients with CVID. A descriptive, cross-sectional and observational study was made including patients with CVID attending Primary Immunodeficiency Clinic of Allergy and Clinical Immunology Department, Specialties Hospital, National Medical Center SXXI, Mexico City. All patients underwent gastrointestinal symptoms questionnaire, laboratory, cabinet, endoscopy and breath test for bacterial overgrowth. We evaluated 17 patients, 8 men and 9 women with an average age of 36 years with a definitive diagnosis of CVID according to international criteria; 59% had abdominal pain, 53% abdominal distension; only 3 patients (17.6%) reported constipation; 47% had chronic diarrhea, of which only 2 (11.8%) had rectal pushing. The diagnoses of gastrointestinal manifestations of this population were: 18% chronic diarrhea, celiac disease and bacterial overgrowth, 24% gastrointestinal functional disorder, 12% constipation and 6% dyspepsia. One patient (6%) had no gastrointestinal symptoms. Prevalence of gastrointestinal diseases in adult patients with common variable immunodeficiency was 94%. There was no gender predominance. It is therefore important that patients with CVID will conduct a study protocol that includes a complete medical history considering gastrointestinal symptoms and signs, in order to determine timely diagnosis and therapeutic approach.

The influence of motor abilities in children with autism spectrum disorder on caregiver experiences: A pilot study

Background: Parents of children with Autism Spectrum Disorders (ASD), particularly mothers, experience a unique caregiving demand. Although benefits do exist, caregivers often report a burden due to children’s lack of social interaction and ability to self-care. Development of motor skills employed in these activities is often delayed in children with ASD; however, possible links between motor skills and the experiences of their caregivers is not clearly understood. This pilot study explored caregivers’ descriptions of the functioning of children with ASD in relation to their children’s motor abilities. Methods: Five children (two male, three female, ages 6‐8) with ASD participated in the following tasks to assess lateral preference and performance: the WatHand Cabinet Test, involving a series of unimanual tasks; the Large and Small Grooved Pegboards test, which time the placement of pegs into key-shaped holes; Eyedness Tasks, such as looking through a tube with one eye; and Footedness Tasks, such as kicking a ball. The five married female primary caregivers (ages 35‐46) of these children participated in one-on-one, semistructured interviews regarding their view of their children’s functioning, and costs and benefits of their experiences. Results: Overall, parents of children who displayed weaker lateralization described their children’s motor abilities in ways that were indicative of greater difficulties with social interaction and age-appropriate selfcare. Conclusions: Implications exist for intervention planning, where service providers should be cognizant of the motor difficulties experienced by children with ASD, and plan interventions that promote functional gains.

The relationship between surface treatments and corrosion resistance of hot-dip galvanized steel

In this work three surface treatments such as: polishing, sand-blast and polishedoxidized have been carried out on the hot-dip galvanized coatings. The roughness and corrosion resistance of coatings have been studied. Surface morphology of coatings has evaluated by scanning electron microscope (SEM). Corrosion behavior was analyzed by salt spray cabinet test and Tafel extrapolation test. The results showed that the sample under sand-blasted treatment exhibited the highest roughness number. Tafel polarization and salt spray cabinet tests reveal the sample with great roughness number have weak corrosion resistance. Difference observed in corrosion behaviour can be explained by difference in surface roughness.

The effect of zinc bath temperature on the morphology, texture and corrosion behaviour of industrially produced hot-dip galvanized coatings

The purpose of this work is to identify the influence of zinc bath temperature on the morphology, texture and corrosion behavior of hot-dip galvanized coatings. Hot-dip galvanized samples were prepared at temperature in the range of 450-480 °C in steps of 10 °C, which is the conventional galvanizing temperature range in the galvanizing industries. The morphology of coatings was examined with optical microscopy and scanning electron microscopy (SEM). The composition of the coating layers was determined using energy dispersive spectroscopy (EDS) analysis. The texture of the coatings was evaluated using X-ray diffraction. Corrosion behavior was performed using salt spray cabinet test and Tafel extrapolation test. From the experimental results, it was found that increasing the zinc bath temperature affects the morphology of the galvanized coatings provoking the appearance of cracks in the coating structure. These cracks prevent formation of a compact structure. In addition, it was concluded that (00.2) basal plane texture component was weakened by increasing the zinc bath temperature and, conversely, appearance of (10.1) prism component, (20.1) high angle pyramidal component and low angle component prevailed. Besides, coatings with strong (00.2) texture component and weaker (20.1) components have better corrosion resistance than the coatings with weak (00.2) and strong (20.1) texture components. Furthermore, corrosion resistance of the galvanized coatings was decreased by increasing the zinc bath temperature.

Down-regulation of AnnexinA2 expression is associated with invasion and metastasis of prostate cancer

Objective To analyze the impact and its mechanism of down-regulation of AnnexinA2 expression on prostate cancer(PCa) invasion and metastasis.Methods The expression of AnnexinA2 in three prostate cancer cell lines with different metastasis ability,including LNCaP (lower metastasis ability),PC3 (lower metastasis ability),C4-2B (higher metastasis ability) were detected by Western blot.The correlations between the expression of AnnexinA2 and the metastasis ability of prostate cancer cells were also evaluated.The siRNA was used in PC3 cells to down-regulate the expression of AnnexinA2,the cell proliferation assay was performed by MTT method,the cell apoptosis level was detected by flow cytometry,the expression of MMP-2 and MMP-9 were detected by Westrn blot,the in vitro invasiveness of PC3 was detected by transwell cabinet test,and the migration ability of PC3 cells was detected by scratch test,respectively.Results The grayscale value of AnnexinA2 expression in C4-2B cells is 0.22,in contrast with the internal reference,which was obviously lower than those of LNCaP and PC3 cells with lower metastasis potency(relative grey value is 0.93 and 0.95,respectively.P＜0.01).After RNAi was used in PC3 cells to down-regulate the expression of AnnexinA2,the growth became faster for PC3-ANXA2-siRNA cells than PC3,PC3-Lip and PC3-empty vector cells (P＜0.05).After RNAi was used in PC3 cells to down-regulate the expression of AnnexinA2,the ratio of apoptosis was detected by flowcytometry in PC3,PC3-Lip,PC3-empty vector and PC3-ANXA2-siRNA cells,and the apoptosis ratio in PC3-ANXA2-siRNA cells was the highest.However,the difference was not significant compare to others (P＞0.05).After RNAi was used in PC3 cells to downregulate the expression of AnnexinA2,the expression of AnnexinA2 in PC3-ANXA2-siRNA cells was decreased while the expression of MMP-2 and MMP-9 were increased.After RNAi was used in PC3 cells to down-regulate the expression of AnnexinA2,invasiveness of PC3-ANXA2-siRNA cells detected by transwell cabinet test was increased in vitro,and migration of PC3-ANXA2-siRNA cells detected by scratch test was increased in vitro.Conclusions The down-regulation of expression of AnnexinA2 could increase the invasive and metastatic ability of prostate cancer,and this may attribute to the up-regulation of MMP-2 and MMP-9 expression in prostate cancer. Key words: Prostate cancer; Annexin A2; Progression; Matrix metalloproteinases

Can an observational method of assessing hand preference be used to predict language lateralisation?

The current study investigated (a) whether or not the WatHand Cabinet Test (WHCT, Bryden, Roy, & Spence, 2007) could be used as accurately as the Waterloo Handedness Questionnaire (WHQ) to classify individuals into language lateralisation groups based on their hand preference, and (b) the relationship between direction and degree of hand preference and language lateralisation. A total of 142 participants (82 right-handers and 60 left-handers) completed the WHQ and the WHCT, and performed a fused-words dichotic listening test. Findings indicated that the WHCT was robust alternative to the WHQ in providing a measure of hand preference as there was a high correlation between the WHCT and the WHQ, and individuals were divided into similar language lateralisation groups when using either the WHCT or the WHQ as the classifying variable. More specifically, there existed a predictable pattern of language lateralisation into which members of different handedness groups fell. The same pattern exists whether handedness is defined using subjective questionnaires or more objective observational measures of hand preference.

Constitutional Power and Competing Risks: Monarchs, Presidents, Prime Ministers, and the Termination of East and West European Cabinets

Some European constitutions give cabinets great discretion to manage their own demise, whereas others limit their choices and insert the head of state into decisions about government termination. In this article, we map the tremendous variation in the constitutional rules that govern cabinet termination and test existing expectations about its effects on a government's survival and mode of termination. In doing so, we use the most extensive government survival data set available to date, the first to include East and West European governments. Our results demonstrate that constitutional constraints on governments and presidential influence on cabinet termination are much more common than has previously been understood and have powerful effects on the hazard profiles of governments. These results alter and improve the discipline's understanding of government termination and durability, and have implications for comparative work in a range of areas, including the survival and performance of democracies, electoral accountability, opportunistic election calling, and political business cycles.

The lighter side of advertising

preference and performance abilities, a cross-sectional sample of 548 children (ages 3–18) and adults (over 19) completed the Waterloo Handedness Questionnaire, the WatHand Cabinet Test (an observational test of hand preference), and the Annett pegboard. Findings revealed that while the direction of hand preference does not change significantly with age, the degree of hand preference does, such that younger children exhibit weaker hand preference than older children and adults. This pattern of hand preference was much more evident for lefthanded individuals, where consistent hand preference was not seen until 8 years of age. Similarly, performance differences between the hands did not emerge for left-handers until later childhood, while in comparison large performance differences were seen for right-handers at all ages. The implications for the development of handedness will be discussed.

An Observational Method of Assessing Handedness in Children and Adults

The current study was performed to assess the WatHand Cabinet Test (WHCT), a newly developed multidimensional observational test of handedness. Because the test is observational, it is ideal for assessing children, as it does not require a high degree of verbal comprehension on the part of the participants. 548 individuals participated in the present study on a voluntary basis. Individuals of varying ages were examined (including 3 to 5, 6, 7, 8, 9, 10, and 11-year-olds, and 19-to 24-year-olds). Each participant was asked to complete the WHCT, the Annett Pegboard (Annett, 1985), and the Waterloo Handedness Questionnaire (WHQ) (M.P. Bryden, 1977). Overall, the total score on the WHCT was significantly correlated with both the WHQ, r =.795, p < .01, and the Annett Pegboard, r = .542, p < .01. Sub-scores measuring skilled performance, bimanual performance, and internal consistency were also examined, as well as performance on the three tests as a function of age. Overall, findings indicate that that the WHCT is a valid test of hand preference in both children and adults. Its ease of use, quick administration, and built-in quantitative sub-scores offer a robust alternative method for measuring hand preference.

A study of zinc phosphate coatings on 12·5Cr–21·0Ni stainless steel

12·5Cr–21·0Ni stainless steel was chemically treated with zinc phosphate in order to find the most suitable phosphate solution and its operating parameters. The phosphate coatings were tested for their corrosion protection of stainless steel using three methods: the salt spray test, the humidity cabinet test and the brine immersion test. The phosphate coatings were also mechanically tested using a tensile test for determining their mechanical properties. Results clearly show that phosphate coatings with a uniform appearance and full coverage can give high corrosion protection to 12·5Cr–21·0Ni stainless steel by forming a physical barrier against the corrosive environment. The 12·5Cr–21·0Ni stainless steel after coating with zinc phosphate still retains reliable mechanical properties, thereby providing valuable applications in the engineering field.

Evaluation of the surface treatment effect on the anticorrosive performance of paint systems on steel

Electrochemical impedance spectroscopy studies were carried out for paint coated carbon steel sheets under free corrosion conditions when exposed to 3.5% NaCl solution for 405 days. Five anticorrosive primers [epoxy-polyamide/red lead/ferric oxide; alkyd/red lead; epoxy/zinc–aluminium; zinc-rich ethyl-silicate and epoxy/zinc phosphate] were used while changing the steel surface treatment condition. The EIS data was interpreted and discussed in terms of the time dependence of the electrical (paint coating) and electrochemical (steel substrate) parameters associated to interfacial processes describing the metal/paint system deterioration. Furthermore, the progress of the coating delamination process was estimated by the empirical expression relating the measured/specific double layer capacitance ratio. Experimental data withdrawn from salt spray cabinet tests performed for 261 days and adhesion measurements are also discussed. On the basis of the electrochemical, visual inspection and standardized tests results it was concluded that the best corrosion performance was provided by the epoxy-polyamide/red lead/ferric oxide anticorrosive paint without any marked effect of the surface treatment; followed by those anticorrosive systems including dry or wet sandblasting in presence of inhibitor. This result has been attributed to the fact that such surface treatments can improve the barrier properties and/or the inhibiting corrosion protection and the steel/paint adhesion properties or reduce the osmotic pressure effect.

Investigation into mechanism of protection of pigmented alkyd coatings using electrochemical and other methods

This paper reports some work conducted on several different alkyd coatings. Electrochemical techniques particularly the electrochemical noise method (ENM) have been used to monitor the performance of two and three coat systems in sodium chloride solutions. For one of the coatings systems comparison has been made between the results from room temperature continuous immersion exposure and accelerated tests both a cabinet test and a high temperature immersion test and good correlation has been obtained. Detached films have also been examined to obtain mechanism information and to clarify how these alkyd coatings work to prevent corrosion. Both the DC resistance characteristics, the noise resistance and the inhibitive properties of extracts have been examined. These tests appear to give information which is useful in deciding how effective the coating will be both when intact and when it needs to protect at a break or scribe. The work provides pointers for investigations of low VOC coatings from renewable resources such as water soluble alkyd–linseed oil coatings.

Efecto de la deformación por tracción sobre la orientación cristalográfica del recubrimiento y la resistencia a la corrosión en CNS de chapas de acero con recubrimientos base cinc

Fil: Sacco, E.A.. Universidad Nacional de La Plata. Facultad de Ingenieria. Departamento de Mecanica. Laboratorio de Investigacion de Metalurgia Fisica; Argentina. Provincia de Buenos Aires. Gobernacion. Comision de Investigaciones Cientificas. Centro de Investigaciones en Tecnologia de Pinturas. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - La Plata. Centro de Investigaciones en Tecnologia de Pinturas; Argentina

Ranking high-quality paint systems using EIS. Part II: defective coatings

The assessment of the protective performance of paint coating systems as described in Part I of this work is a valuable procedure for intact coatings. However when defects are present in the paint films the significance of tests using intact coatings is limited, since the mechanisms involved in degradation/healing of the painted metal could change. Thus the full knowledge of the degradation behaviour of coated metals should involve both situations, requiring the use of the two types of specimens, i.e., with intact and defective coatings. In order to meet the industry requirements in terms of time, accelerated cabinet tests in scribed coated specimens can be associated with intermediate temperature tests in intact coatings using EIS measurements (Part I).