Cracking Research Articles

Physiological Disorders and Fruit Quality Attributes in Pomegranate: Effects of Meteorological Parameters, Canopy Position and Acetylsalicylic Acid Foliar Sprays.

Meteorological parameters and occurrences of cracking (CR), russeting (RS), and sun scald (SS) symptoms were monitored in a pomegranate cv. “Wonderful” orchard planted in a W–E orientation, during a 3-year study. Moreover, the efficacy of preharvest foliar sprays with acetylsalicylic acid (ASA; 0.5 mM or 1.0 mM), applied biweekly four to six times, on yield and fruit quality attributes were evaluated in a 2-year study. Fruit from the N-side of the canopy had greater CR and RS, whereas SS symptoms were lower, compared with the S-exposed part of the canopy. The N-side of the canopy had also substantially lower fruit number and yield, suggesting for an important role of light on bisexual flower formation and/or fruit set. Following the occurrences in CR and RS during the fruit maturation period, it was found that temperature fluctuation was the main cause. The presence of RS damages may also be related with increased relative humidity and water movement as symptoms were higher in years with higher values, in the N-side of the canopy and often occurred in the exposed and stylar end of the fruit. The ASA treatment substantially reduced RS by up to 57%, improved the peel red coloration, while anthocyanin, antioxidant capacity, and soluble solid contents in juice were higher. Foliar sprays with ASA did not affect yield, but induced a trend of bigger-sized fruit. In conclusion, planting in a N–S row orientation and selecting an orchard plantation site with a minimum temperature fluctuation and low relative humidity during the fruit-ripening period are measures to control CR and RS in pomegranate. ASA foliar applications proved to have beneficial effects on juice antioxidant contents, but more importantly on fruit appearance.

Highway subsurface assessment using pavement surface distress and roughness data

In this paper, pavement sections of the highway connecting Jeddah to Jazan were selected and analyzed to investigate the relationship between International Roughness Index (IRI) and pavement damage including cracking, rutting, and raveling. The Ministry of Transport (MOT) of Saudi Arabia has been collecting pavement condition data using the Road Surface Tester (RST) vehicle. The MOT measures roughness (ROU), rutting (RUT), cracking (CRA), and raveling (RAV). Roughness measurements are calculated in terms of the International Roughness Index (IRI). In the present three relationships, including CRA versus IRI, RUT versus IRI, and RAV versus IRI have been developed. The models relating to three types of distresses under study, and model relating IRI to ride quality have been studied in the present work. The results of the analysis indicate that a significant relationship exists between IRI and cracking, and IRI and raveling at 95% confidence level. The results also show that the rutting did not show a significant relationship to IRI values. It can be concluded from the results that cracking and raveling may possibly be described as ride quality distresses, whereas the rutting distress may be described as non-ride quality distress. The results indicate that while statistically significant relationships exist between IRI and both cracking and rutting, these relationships are not strong enough for IRI to be used as a surrogate measure for pavement condition.

Study the Relationship between Pavement Surface Distress and Roughness Data

In this paper, pavement sections from the highway connected Jeddah to Jazan were selected and analyzed to investigate the relationship between International Roughness Index (IRI) and pavement damage including; cracking, rutting, and raveling. The Ministry of Transport (MOT) of Saudi Arabia has been collecting pavement condition data using the Road Surface Tester (RST) vehicle. The MOT measures Roughness, Rutting (RUT), Cracking (CRA), raveling (RAV). Roughness measurements are calculated in terms of the International Roughness Index (IRI). The IRI is calculated over equally spaced intervals along the road profile. Roughness measurements are performed at speed between at 80 kilometers per hour. Thus RST vehicle has been used to evaluate highways across the country. The paper shows three relationships including; cracking (CRA) verses roughness (IRI), rutting (RUT) verses IRI, and raveling (RAV) verses IRI. Also, the paper developed two models namely; model relates IRI to the three distress under study, and model relates IRI to ride quality. The results of the analysis claim at 95% confidence that a significant relationship exist between IRI and cracking, and raveling. It’s also shown that rutting did not show significant relationship to IRI values. That’s leads to conclude that the distresses types: cracking and raveling may possibly be described as ride quality distresses at different level of significant. Rutting distress described as non-ride quality type’s distresses.

Development of Pavement Condition Rating Model and Pavement Roughness Model for Saudi Highways

The Pavement Condition Rating (PCR) has been used by the Ministry of Transport (MOT) in Saudi Arabia to report pavement condition. The World Bank developed the PCR in 1986. PCR is based on International Roughness Index (IRI), Rutting (RUT), Cracking (CRA), and Raveling (RAV). The MOT collects pavement condition data using a digital inspection vehicle called Road Surface Tester (RST) vehicle. On some expressways, the MOT measures the Skid Number (SN) using a Skid Test Unit as complimentary measurement for safety issues. The objective of this paper is to develop PCR model and pavement roughness model using survey data for overlaid sections on some expressways in the network with total observation number is 3469. The PCR model is a function of pavement age (T), Traffic Volume (TV), and IRI. The IRI model is a function of RUT, RAV, and CRA. Overlaid sections across the entire network have been selected to study the mechanisms of pavement deterioration, to develop the model and to draw conclusions.

Ni/SiO<SUB>2</SUB> Catalyst for the Selective Ring Opening of Methylcyclopentane

The selective ring opening (SRO) of methylcyclopentane (MCP) catalyzed by 60 wt.% Ni/SiO2 has been studied. The highly loaded and well dispersed Ni/SiO2 catalyst was prepared by coprecipitation method and their surface characteristics were evaluated through H2-TPR, NH3-TPD, H2-chemisorption, XRD, SEM and TEM. The effect of different reaction temperature, H2 pressure, and WHSV on SRO of MCP was also investigated in the vapor phase reactor. The SRO of MCP produces n-hexane (n-H), 2-methylpentane (2-MP) and 3-methylpentane (3-MP) as desired RO products for the improvement of cetane number (CN) in fuel, along with some side products, such as cyclohexane as well as C1–C5 fragments as a ring enlargement (RE) and cracking (CR) products, respectively. Ni/SiO2 catalyst showed an unprecedented high catalytic performance with conversion 68.5% and 81.6% of RO products selectivity.

Thermodynamic equilibrium analysis of ring opening of decalin

Thermodynamic equilibrium calculations were carried out in order to understand the effect of temperature and hydrogen-to-hydrocarbon ratio on the yield and selectivity of ring opening products that are obtained from hydrocracking of decalin. Thermochemical analysis of single hydrocracking reactions involving selected alkanes and naphthenes indicates that endocyclic cracking of naphthenes is less favored than acyclic and exocyclic cracking reactions due to entropy considerations. The equilibrium calculations were performed in the temperature range 298–800K at a pressure of 1bar for a mixture of compounds obtained from hydrocracking of decalin using the assumption that the reaction mixture behaves as an ideal gas. The quantum chemical method G3MP2 was used to calculate the standard Gibbs free energy of formation for compounds for which thermochemical data are so far unavailable in the open literature. The results from equilibrium calculations indicate that, as long as cracking (CR) and dehydrogenation (DH) products are allowed to form simultaneously, total ring opening (TRO) products cannot be present in the reaction mixture in appreciable concentrations. If the pathways leading to the formation of CR products are excluded from the equilibrium calculations, the yield of TRO products reaches a significant value of ∼0.75kg/kg decalin fed in the temperature range 400–500K. The highest yield of TRO products, ∼1kg/kg decalin fed, observed for a hydrogen-to-hydrocarbon ratio of 4 in the temperature range <500K could be the maximum achievable yield for TRO products of decalin. The TRO products consist mostly of saturated ring opening (SRO) products and traces of unsaturated ring opening (USRO) products.

A project aiming at the enhancement of NDT{\&amp;}E of stress corrosion cracking

This paper introduces a research project the authors have proposed. The project aims to gather non-destructive testing data of stress corrosion cracking specimens and present them as benchmark data freely available to researchers in the field. Round-robin test using seven austenitic stainless st eel plate specimens with artificial stress corrosion cracki ng is carried out, and they are measured using various non-destructive testing methods. The data measured are made available together with the results of destructive tests to confirm the true profile of the cracking.

Hydroconversion of methylcyclopentane over Pt/HZSM-5 catalyst: I. Effects of reaction parameters on ring enlargement reaction

The effects of reaction parameters such as temperature, pressure, and hydrogen to hydrocarbon ratio (H 2/HC) on the hydroconversion of methylcyclopentane (MCP) over Pt/HZSM-5 have been investigated in a fixed-bed down-flow reactor. The catalytic evaluation results were compared with the thermodynamic calculation data in order to investigate the behavior of MCP Ring enlargement (RE) reaction. Methylcyclopentane hydro conversion is described as a linear combination of three reactions: ring enlargement (RE), ring opening (RO) and cracking (CR), and RE reaction produces cyclohexane (CH) and benzene (Bz). It was shown that the conversion of MCP increased with the increase in temperature or with the decrease in H 2/HC ratio, whereas decreased with the increase of pressure. The influence of the reaction parameters on the RE selectivity presented a complicated picture. With the increase in temperature, the RE selectivity first increased and then decreased, showing a maximum at a certain temperature. The effect of the H 2/HC mol ratio was found to be relevant with temperature. At lower reaction temperatures, the RE selectivity decreased with decrease in the H 2/HC ratio. However, at higher reaction temperatures, the H 2/HC mol ratio had little influence on RE selectivity. The distribution of RE products between CH and Bz provides information on the reaction pathway. The experimental Bz/CH ratio was in excess of the equilibrium value, which strongly suggested that Bz, as the same as CH, could be a primary product from MCP. Thus, a modified reaction pathway of RE reaction could be proposed as follows: both CH and Bz were produced from the same intermediate, which was an adsorbed species on the dual function catalyst formed from MCP. In other words, the isomerization and dehydroisomerization are parallel reactions, producing CH and Bz, respectively. Meanwhile, Bz can come from CH through dehydrogenation.

Fracture analysis of a high-strength concrete and a high-strength steel-fiber-reinforced concrete

This paper addresses the use of R-curves to study the fracture behavior of high-strength concrete and steel-fiber-reinforced concrete subjected to crack ing in a three-point bending configuration. The R-curves are modeled through an effective approach based on the equations of linear-elastic fracture mechanics (LEFM), which relates the applied load to the fundamental displacements of notched-through beams loaded monotonically. It is initially shown that, for quasi-brittle materials, the R-curves responses can be evaluated in a quasi-analytical way, using the load-crack mouth opening, the load-load line displacement, or exclusively the displacement responses obtained experimentally. Afterward, the methodology is used to obtain the fracture responses of high-strength and fiber-reinforced concretes, up to the final stages of rupture.

Petroleum Classification Based on the Ratio of Sulfur to Nitrogen: Application in the East Texas Basin

ABSTRACT Petroleum families are characterized by limited ranges of organic sulfur to nitrogen (S/N) ratios, despite thermal crack ing. In the East Texas Basin three families are recognizable on the basis of both carbon isotopic and S/N ratio data. Jurassic oils possess modal saturated hydrocarbon values of -25% 13C and S/N ratios close to 20; Lower Cretaceous oils, values of -26 and 10, and Upper Cretaceous oils, values of -28 and 3. Numerous published analyses of sulfur and nitrogen in oils facilitated mapping the detailed geographic distributions of the families recognized. Both source rock and petroleum data demonstrate that Upper Cretaceous oil, including that of the supergiant East Texas field, was generated only beyond the confines of the East Texas basin, principally to the south and west in the Gulf Coast basin. Migration distances to present pool sites are of the order of 30 to 200 miles. End_of_Record - Last_Page 602-------

Prediction of Transverse Cracking and Stiffness Reduction in Cross-Ply Laminated Composites

A modified shear lag analysis, taking into account the concept of in terlaminar shear layer, is employed to predict the onset of a transverse crack and multiple transverse cracking. In this analysis, the boundary conditions are satisfied for any trans verse crack spacing. The crack multiplication is simulated by adjusting the crack spacing. Based on this analysis the laminate stiffness reduction due to the multiple transverse crack ing is also evaluated in cross-ply laminated composites. The energy concept is utilized to assess the effect of 90° layer thickness and the constraining effect of 0° layer on the trans verse cracking behavior of cross-ply laminated composites. Predictions of the onset of a transverse crack and stiffness reduction due to transverse cracks are compared with those of previous analyses and existing experimental data. The present analysis is simple, yet its results show reasonable agreement with experimental results.

Impact Resistance of Cross-Plied Polyphenylene Sulfide Composites

Impact resistance and residual strength of thermoplastic polyphenylene sulfide (PPS) composites are studied with regard to laminate configurations consisting of cross-plied Glass/PPS, 50% hybrid Glass/Graphite/PPS and Graphite/PPS. By means of impact testing, ballistic limit measurements show that hybridization can be used to modify penetration resistance. Residual strength measurements show that the percent reduction in strength is about 50% for all the laminate configurations The original strength values are Glass/PPS-440 MPa (63 ksi), 50% hybrid Glass/Graphite/PPS-530 MPa (76 ksi), and Graphite/PPS-585 MPa (84 ksi). For microstructural comparison of the damage modes and progression, two series of impact tests were done In one series, impact was inhibited such that only damage initiation was possible, and in the second series, the impact was allowed to a completion. Three impact velocities, 10 m/sec, 20 m/sec, and 30 m/sec were used. Microstructural observation of damage initiation alone revealed matrix cracking in Glass/PPS, delamination in Glass/Graphite/PPS, and spalling of Graphite/PPS. Further, upon completion of impact, Glass/PPS is minimally perforated and exhibits matrix crack ing and delamination, Glass/Graphite/PPS is delaminated and matrix cracking has oc curred and there is shear cut-out, and Graphite/PPS is severely sheared and forms a plug. Thus, by evaluating the microstructure after damage initiation and completion, the damage development and progression for each configuration is described.

Effect of fabrication procedure on liquid metal embrittlement cracking in welded steel structures by molten zinc

This study deals with the estimation of occurrence and preventive condition of the Liquid Metal Embrittlement cracking (LMEC) due to hot dip galvanizing using Y-Groove Crack ing Test pieces.The results obtained are as follows, (1) Using Y-Groove Cracing Test piece is appropriate for the estimation test of the LMEC in welded steel structures.(2) The critical condition for LMEC occurrence is indicated by the relation between the intensity of restraint and the maximum hardness in HAZ (Hv max.).(3) The LMEC preventive condition for welded steel structures to be galvanized are obtained by the Hv max. under the condition that welded joints have the most severerity value of the intensity of restraint in each type of structure. For example, the LMEC preventive condition of weldment in transmission tubular tower structures is assumed that Hv max. keeps less than 260.

Substrate Deformation Studies on Impact Erosion and Plowing by Photoelasticity

Static and dynamic photoelasticity methods were applied in studying the mechanisms of erosion. A multiple spark camera and a linear gas gun were used to photograph impact-induced dynamic stress waves. The propagation of stress waves in a polycarbonate material was analyzed upon impact of a 3-mm diameter rigid ball traveling at 50 m/s velocity. The role of pressure, shear, and Rayleigh waves in causing damage was found to be low. The residual stress field generated due to particle impact was determined using a circular polari scope. It was found that the plastic deformation at impact-induced high strain rates and the residual stress field generated by repeated impacts produce crack ing, and the interaction of these cracks results in erosion loss. Impact on brittle Columbia resin produced lateral, circumferential, and radial cracks, resulting in material removal. The stress gradient and cracking were also studied during plowing on the above two materials.

溶接鋼構造物の溶融金属脆化割れに及ぼす施工条件の影響

This study deals with the estimation of occurrence and preventive condition of the Liquid Metal Embrittlement cracking (LMEC) due to hot dip galvanizing using Y-Groove Crack ing Test pieces.The results obtained are as follows, (1) Using Y-Groove Cracing Test piece is appropriate for the estimation test of the LMEC in welded steel structures.(2) The critical condition for LMEC occurrence is indicated by the relation between the intensity of restraint and the maximum hardness in HAZ (Hv max.).(3) The LMEC preventive condition for welded steel structures to be galvanized are obtained by the Hv max. under the condition that welded joints have the most severerity value of the intensity of restraint in each type of structure. For example, the LMEC preventive condition of weldment in transmission tubular tower structures is assumed that Hv max. keeps less than 260.

Susceptibility to hydrogen-induced delayed failure of temperembrittled, low-alloy steel

A commercial 1Cr-1 Mn steel has been investigated in the temper-embrittled condition in relation to sensitivity to hydrogen stress cracking. The work involved delayed brittle failure tests on smooth steel specimens which were stressed in tension under constant load, while being charged with cathodic hydrogen at a constant current density. Both the relative range of stresses for susceptibility to hydrogen stress crack ing and the overall rate of delayed failure were found to be maximal for specimens which had been tempered at 500 - 550 C, i.e. where grain-boundary impurity segregation and temper embrittlement were also at a maximum. While the intergranular weakness induced by impurity segregation appears to be responsible for lowering the time required to propagate a crack to the critical point for delayed failure, some interaction between hydrogen and impurity elements appears to cause the increase in susceptibility to hydrogen stress cracking.