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A crucial factor that affects all composite materials exposed to typical service conditions is environmental degradation . It has been shown that over time the combination of moisture and fluctuating temperatures degrades the structure of polymeric composites through chemical and morphological degradation mechanisms. Experimental investigations have not only demonstrated degradation of the polymeric matrix but also of the CNF–matrix interface due to surface morphology variation caused by weathering. This chapter aims to focus on the moisture effects on the structure and mechanical properties of CNF/polymer composites in an effort to offer insight into the mechanisms of degradation and failure under load after moisture exposure. However, information on this aspect of CNF/polymer composites is in the nascent stage and extensive future work is required.

The Spanish Technical Building Code published in 2006 regulates the basic requirements of building façades to prevent the inadequate presence of atmospheric water inside Spanish buildings. The moisture exposure estimate, based on several climate parameters, allows adjusting these requirements for every location and façade. However, the parameters used by the Spanish Code can be improved, resulting in a more appropriate estimate of the required water tightness degree and thus in an improvable allocations of the necessary design conditions. This paper reviews these parameters, presenting other internationally applied, and analyses the moisture exposure in the Spanish territory, which would allow improving the subsequent performance of the basic requirements imposed to the façades., El Código Técnico de la Edificación aprobado en 2006, asigna por primera vez en España diferentes requisitos básicos para los cerramientos verticales de edificación, destinados a limitar el riesgo de presencia inadecuada de humedad en el interior de los edificios. La solicitación por humedad, estimada mediante diversos parámetros climáticos, permite ajustar la exigencia de estos requisitos para cada emplazamiento y fachada. Sin embargo, estos parámetros presentan actualmente posibilidades de mejora que pueden dar lugar a una asignación más adecuada del grado de impermeabilidad y con ello, de los requisitos de diseño necesarios. Este artículo revisa estos parámetros climáticos, presenta otros utilizados internacionalmente para el mismo propósito y caracteriza en el territorio español los factores que determinan la solicitación por humedad, haciendo posible mejorar la prestacionalidad de los requisitos básicos impuestos para las fachadas de los edificios.

When durability of EIFS-clad houses located in some coastal ar eas with high moisture exposure was questioned, the EIFS industry introduced new solutions. Most of the newly developed EIFS products are based on the prem ise that a weather resistant, continuous, exterior skin can be difficult to achieve, let alone maintain, during the service life of a building. These new systems have two identifiable features: (1) EIFS cladding and (2) a multifunctional second-line of de fense to contain and manage water that passed the cladding. Three subsystems and systems, namely, source drained (SD-EIFS), drained screen (DS-EIFS), and vented screen (VS-EIFS), rely on water drainage from the wall assembly. The fourth multifunctional EIFS is primarily based on the storage and drying capabilities of the wall assembly. Another prerequisite of a functional wall assembly is the presence of an air barrier. Experience indicates that only the redundant wall system with multiple defense mechanisms presents the opportunity for a durable and low-maintenance building envelope.

Objective: To investigate the surface hardness of four conventional glass-ionomer cements: Ketac-Molar (KM), HiFi (HF), Vivaglass Fil (VF), Ketac-Fil (KF) and a newly developed glass polyphosphonate based cement, Diamond Carve (DC) at different maturation times in water and to investigate the effects of early water exposure on their surface hardness. Method: Disc specimens (10 mm diameter, 1 mm thick) were prepared and mould stored at 37°C. The effect of different maturation times (15, 30 and 60 min) and storage in water over 24 h after those maturation times on surface hardness was determined using a microindentor with a Vickers diamond indentor. The results of the surface hardness tests were analysed using Mann-Whitney non-parametric statistics (p≤0.05). The working (WT) and setting (ST) times of the cements were also measured using a modified Wilson oscillating rheometer. Results: All the materials became harder after 24 h immersion in water. HF, VF and DC showed initial sensitivity to a short maturation time, but only HF was adversely affected by early moisture exposure. KF and KM were least sensitive to short maturation time or early water exposure. DC had the shortest and HF the longest WT and ST. HF and VF had a high WT:ST ratio of 1:7 and 1:9, respectively. Conclusions: A short maturation time (of 15 min) and early exposure to water did not adversely affect the surface hardness of KF, KM, VF and DC. DC, based on poly(vinyl phosphonic acid), had the shortest WT and ST. Poly(acrylic acid) based HF and VF had a long ST in relation to their WT.

The feasibility of using near infrared light transmission, obtained after drying, to predict if an almond would develop concealed damage after roasting was studied. It was observed that, after drying, nuts with concealed damage have less absorbance in the oil absorption band at 930 nm and increased absorbance in the region between 700 and 750 nm. From near infrared transmission spectra obtained after drying, discriminant analysis was used to classify nuts as concealed damaged or undamaged; validation classification error rates as low as 12.4% were obtained. The effect of drying temperature, and moisture exposure, on the incidence of almonds with concealed damage was also studied. The use of a lower temperature drying treatment can reduce the incidence of concealed damage. The incidence of concealed damage for nuts receiving the same moisture treatment was 44.4 and 1.2% when dried at 110 and 55 °C, respectively.

The effect of short-term environmental exposure on the response of in situ formed externally composite strengthened concrete is investigated. Measured response from static loading is described in terms of environmental degradation of composite and composite-concrete interface. Results indicate that degradation occurs primarily at the level of the resin in contact with the concrete, and that due care should be taken of changes in composite stiffness due to moisture exposure and consequent resin plasticization, as well as due to stiffness increases under cold conditions.

Carpet tack strips offer an excellent tool to interpret the occurrence and duration of a water loss. Water losses are among the most common claims in the United States. When a water loss occurs in a carpeted home, the carpet tack strips offer a precise method to evaluate the duration of the event based on various characteristics of staining and deterioration. Research studies compared the sequential changes that occur when carpet tack strips are exposed to continuous moisture for one week periods of wetting and drying over a period in excess of 2 years. Research using carpet tack strips exposed to continuous and cyclical wet–dry periods of moisture exposure revealed visual and microbial clues that prove effective in differentiating the duration of a loss and whether the loss originated from a single or repeated event. Forensic engineers and scientists will discover that a carpet tack survey will expose the water release history of a structure and guide them to more accurate and defensible evaluations of a water damage claim.

[218274-18-1] C13H22O9 (MW 322.31) InChI = 1S/C13H22O9/c1-10(14)17-4-7-20-13(21-8-5-18-11(2)15)22-9-6-19-12(3)16/h13H,4-9H2,1-3H3 InChIKey = SJRSGWRVRYHUBT-UHFFFAOYSA-N (reagent used as a protecting group for the 2′-hydroxyl group in RNA synthesis) Alternate Name: ACE. Physical Data: bp 140 °C, 20 mmHg. Solubility: soluble in most organic solvents. Form Supplied in: colorless liquid. Purification: distillation. Analysis of Reagent Purity: elemental analysis, MS, NMR. Handling, Storage, and Precautions: tris(2-acetoxyethoxy)orthoformate is a stable oil that can be stored in a bottle without precaution to air and moisture exposure.

Cornerstone Research Group Inc. (CRG) has developed environmental exposure tracking (EET) sensors using shape memory polymers (SMP) to monitor the degradation of perishable items, such as munitions, foods and beverages, or medicines, by measuring the cumulative exposure to temperature and moisture. SMPs are polymers whose qualities have been altered to give them dynamic shape "memory" properties. Under thermal or moisture stimuli, the SMP exhibits a radical change from a rigid thermoset to a highly flexible, elastomeric state. The dynamic response of the SMP can be tailored to match the degradation profile of the perishable item. SMP-based EET sensors require no digital memory or internal power supply and provide the capability of inexpensive, long-term life cycle monitoring of thermal and moisture exposure over time. This technology was developed through Phase I and Phase II SBIR efforts with the Navy. The emphasis of current research centers on transitioning SMP materials from the lab bench to a production environment. Here, CRG presents the commercialization progress of thermally-activated EET sensors, focusing on fabrication scale-up, process refinements, and quality control. In addition, progress on the development of vapor pressure-responsive SMP (VPR-SMP) will be discussed.

[2554-06-5] C12H24O4Si4 (MW 344.66) InChI = 1S/C12H24O4Si4/c1-9-17(5)13-18(6,10-2)15-20(8,12-4)16-19(7,11-3)14-17/h9-12H,1-4H2,5-8H3 InChIKey = VMAWODUEPLAHOE-UHFFFAOYSA-N (reagent for the vinylation of aryl halides,1 building block for carbosilane dendrimers2) Physical Data: bp 224–224.5 °C Solubility: soluble in most organic solvents. Form Supplied in: clear oil Purification: distillation. Handling, Storage, and Precautions: 2,4,6,8-Tetraethenyl-2,4,6,8-tetramethylcyclotetrasiloxane is a stable oil that can be stored in a bottle without precaution for air and moisture exposure.

Moisture can play a critical role in the long-term failure of low-voltage oil-impregnated- paper insulated cables. The processes leading to incipient discharges and, over longer periods, to cable failure are considered. Measurements of commercially manufactured cable insulation conductivity are reported with cycling of temperature and ambient moisture levels. Moisture ingress into cable insulation is also directly measured using Karl-Fischer (KF) titration. Rapid increase in cable core temperature is shown to dramatically increase conductivity for a short period. Cycling of moisture exposure is shown to gradually increase insulation conductivity in both wet and dry states.

Effects of moisture exposure before cure of Scotchply 1009 composite material have been studied by three thermal analysis methods. These studies revealed the need for state-of-the-art analytical tools as well as increased attention to detail in packaging (by supplier) and improved handling (by user to reduce moisture exposure). It is shown that water definitely has a detrimental effect on the cure of Scotchply 1009 prepreg containing a boron trifluoride monoethylamine curing agent. Exposure to moisture greater than 70% RH (relative humidity) can be detrimental and lower the T/sub g/ of Scotchply 1009. Cure temperature high enough to ensure sufficiently high T/sub g/ in 1009 material which has been exposed to moisture can result in degradation of the thermosetting resin. In the manufacture of stator coils, this could cause degradation of electrical properties. >

This Cooperative Research and Development Agreement was a one year effort to make the surface inspection machine based on diffuse reflectance infrared spectroscopy (Surface Inspection Machine-Infrared, SIMIR), being developed by Surface Optics Corporation, perform to its highest potential as a practical, portable surface inspection machine. A secondary purpose was to evaluate applications that would serve both the private and the public sector. The design function of the SIMIR is to inspect sandblasted metal surfaces for cleanliness (stains). The system is also capable of evaluating graphite-resin systems for cure and heat damage, and for measuring the effects of moisture exposure on lithium hydride, corrosion on uranium metal, and the constituents of and contamination on wood, paper, and fabrics. Surface Optics Corporation supplied LMES-Y12 with a prototype SOC-400 that was evaluated by LMES-Y12 and rebuilt by Surface Optics to achieve the desired performance. LMES-Y12 subsequently evaluated the instrument against numerous applications including determining part cleanliness at the Corpus Christi Army Depot, demonstrating the ability to detect plasticizers and other organic contaminants on metals to Pantex and LANL personnel, analyzed sandblasted metal contamination standards supplied by NASA-MSFC, and demonstrated to Lockheed Martin Tactical Aircraft, marietta, GA, for analyzing the paint applied to the F-22 Fighter. The instrument also demonstrated the analysis of yarn, fabric, and finish on the textiles.

Positively charged impurities were introduced into a bilayer graphene (BLG) transistor by n-doping with dimethylformamide. Subsequent exposure of the BLG device to moisture resulted in a positive shift of the Dirac point and an increase of hole mobility, suggesting that moisture could reduce the scattering strength of the existing charged impurities. In other words, moisture screened off the 'effective density' of charged impurities. At the early stage of moisture screening the scattering of hole carriers is dominated by long-range Coulomb scatter, but an alternative scattering mechanism should also be taken into consideration when the effective density of impurities is further lowered on moisture exposure.

Highly ordered mesoporous titania films were synthesized within a short time period by controlling the pH of sols and moisture exposure of as-prepared films.

The irreversible effects of moisture exposure on anhydride-crosslinked epoxy resin films are investigated by means of Fourier-transform infrared spectra. Hydrolytic attack of water at the ester linkages is accelerated in alkaline media and is a mechanically activated process. Matrix hydrolysis is also enhanced in the presence of inorganic fillers.

Auger electron spectroscopy and depth profiling have been used to obtain information on the composition of oxide films formed on high purity Al-5.5Zn-2.5Mg alloys as a function of heat treatment, grain size, storage environment, and temperature. These studies show that in the as heat treated condition the oxide film is predominantly MgO. The Mg/O peak to peak height ratio of this oxide is sensitive to the heat treatment temperature and exhibits a maximum at 475 C. During subsequent storage, especially in a moist environment, this film undergoes substantial changes in composition. The Mg/Al ratio of the oxide decreases due to formation of an Al rich oxide on top of the as heat treated oxide. A model is proposed to account for the changes in the oxide film composition during growth of the Al rich oxide, and possible implications to pre-exposure embrittlement and stress corrosion cracking (SCC) are discussed.

The rapid and varied growth of modern technology has created many new requirements for large industrial motors employing form-wound pre-insulated coils. In an increasing percentage of these applications a motor is required to operate with a high degree of reliability under severe environmental conditions that may adversely affect the insulation system of the machine.1,2,15,4,5,6 Further, the trend toward less elaborate motor enclosures increases the exposure of the insulation to the degrading environmental influences. This has magnified the necessity for providing an insulation system possessing the capability of resisting the environmental influences. The type of environmental conditions referred to are found in the chemical, rubber, food, and plastics industries, where machines may be exposed to direct water spray or highly humid conditions, due to “washing down” operations with water or steam. Also, in pipe line and utility applications, essentially open motors are placed in outdoor locations that afford little, if any, protection from the elements. In still other instances, motors may even be flooded due to weather extremes. In some applications, degrading chemicals may be present in the form of solutions or suspensions. However, regardless of the type of chemical contaminant, it is of prime importance that insulation systems for motors operating in such environments be highly resistant to moisture penetration. Consequently, considerable effort has been expended by motor manufacturers in an attempt to develop insulation systems capable of providing trouble-free service under severe operational environments. The end users have recognized the problem by requiring nonstandard acceptance tests. In some cases, contractual requirements have specified that units for particular applications be capable of passing high potential tests and/or maintaining a minimum insulation resistance while submerged in water for a specified time. This is in addition to the ASA C-50 final acceptance tests.

This paper introduces two demonstration objects onto which various interior insulation systems made of woodfibre have been installed. Temperature and humidity sensors have been integrated in the respective constructions. Insulation systems adhered to the existing construction with clay mortar are compared to non-plastered insulation systems. The drying up process of the clay is of great interest. Additionally the functionality of woodfibre boards on earth-adjacent masonry is studied. Masonry samples give an indication of the existing construction's moisture exposure. In conclusion, the insulation systems’ functionality will be assessed based on measurement results and possible risks of damage.

Moisture problems have perennially plagued the use of the electrical and electronic products. Carbon composition resistors represent a widely used component which must withstand the effects of moisture. Continual improvements in construction and materials have made this possible. To illustrate and magnify the changes that occur in commercial composition resistors with moisture exposure, molded resistors were prepared without insulating jackets or impregnant. Moisture changes are demonstrated to be largely reversible by drying and to be cumulative on extended or repeated moisture exposure. A good correlation was obtained between changes in length and resistance during moisture exposure. An impregnating wax is shown to reduce greatly the moisture susceptibility of the model resistors. Some comparative results obtained with different types of resin binder are also shown, indicating the significant contribution of this phase.

A comparative investigation of polyimide/Cu interface degradation has been carried out for ultrathin photosensitive, non-photosensitive, and preimidized polyimide precursor films cured while in contact with a Cu substrate. The role of curing byproducts and environmental conditions on interface degradation has been elucidated by means of X-ray photoelectron spectroscopy. Immediately after curing, we observed some oxidation of the Cu in contact with non-photosensitive and photosensitive polyimide overlayers. On the other hand, only negligible oxidation was observed for the preimidized polyimide/Cu interface. Experiments in which samples were stored in vacuum, air and a humidity chamber show a dependence of the oxidation kinetics on air/moisture exposure. Preimidized and photosensitive polyimide/Cu interfaces, stored in air, became more extensively oxidized with time relative to identical samples stored in vacuum. Moreover, all three polyimide/Cu interfaces exhibited significantly more oxidation after 3 days in a humidity chamber than after 19 days of storage in air. Taken together, these data clearly demonstrate that absorbed water and its interaction with curing byproducts are key factors in the extent of Cu oxidation at the interface.

A sample of titanium metal powder QC 1779 was subjected to five different treatments of dyring and moisture exposure to estimate the effectiveness of normal drying and handling procedures used in the pyrotechnics processing. The treatments were drying in air, drying in two different vacuum furnaces, exposure to normal humidity, and exposure to 100 percent humidity. Statistical evaluation of the NMR results indicates that there is a significant difference between the moisture content of each treatment. Although the combined effects of temperature, pressure, humidity, and treatment time were not studied in a designed manner to determine their significance on the effectiveness of the drying techniques and moisture uptake by sample QC 1779, the experimental evidence does indicate that all four variables do affect the results of the treatments. 2 figures, 6 tables.

Ribbon parachute fabrics were tested during development and production of a 24 ft parachute, and after 2.5 years ambient exposure at several storage sites. The effects of sewing, packing, and parachute deployment on material strength were obtained in the 1000 lb Kevlar ribbon after moisture exposure during packing, and when packed parachutes absorbed moisture or were thermal cycled. Individual yarn samples from the low strength ribbons exhibited little change in strength indicating that the material itself had not degraded. Factors leading to the change in ribbon strength are discussed. Considering all materials, there have been no indications to date of any uncontrollable changes in material strength that would limit the use of Kevlar in parachute applications.

Russeting (periderm formation) is a critical fruit-surface disorder in apple (Malus × domestica Borkh.). The first symptom of insipient russeting is cuticular microcracking. Humid and rainy weather increases russeting. The aim was to determine the ontogeny of moisture-induced russeting in ‘Pinova’ apple. We recorded the effects of duration of exposure to water and the stage of fruit development at exposure on microcracking, periderm formation and cuticle deposition. Early on (21 or 31 days after full bloom; DAFB) short periods (2 to 12 d) of moisture exposure induced cuticular microcracking—but not later on (66 or 93 DAFB). A periderm was not formed during moisture exposure but 4 d after exposure ended. A periderm was formed in the hypodermis beneath a microcrack. Russeting frequency and severity were low for up to 4 d of moisture exposure but increased after 6 d. Cuticle thickness was not affected by moisture for up to 8 d but decreased for longer exposures. Cuticular ridge thickness decreased around a microcrack. In general, moisture did not affect cuticular strain release. We conclude that a hypodermal periderm forms after termination of moisture exposure and after microcrack formation. Reduced cuticle deposition may cause moisture-induced microcracking and, thus, russeting.