High R-value Research Articles

Clarification of Extremely High R-Value Mechanism of the Electro-Deposited Pure Iron

Electro-deposited pure iron has a very sharp and isotropic <111>//ND fiber texture and a needle shaped grain elongated in the ND. This pure iron exhibits an r-value of over 7, and it is difficult to explain such a high r-value only from the texture. Specific {110} plane slips, which are perpendicular to the sheet surface, exclusively act in this material and this limitation of the active slip system is the main mechanism behind the extraordinarily high r-value. Thus, tensile deformation by this slip system doesn’t require a decrease in thickness. In this study, the mechanism of this slip system limitation is investigated. Because both the {110} slip plane and grain boundary are perpendicular to the sheet surface, the slip plane can easily connect with adjacent grains. This good continuity of slip plane with adjacent grain may have an influence on the choice of slip system.

A review of high R-value wood framed and composite wood wall technologies using advanced insulation techniques

The main objective of this study is to indentify advanced wall frame assemblies applicable for residential and small commercial buildings, that have or could reach R-values larger than RSI – 3.5m2K/W (U-value lower from 0.29). An extensive literature review of existing and past practices is used as the main vehicle to analyze: framing and wall insulation methods, architectural details with focus on minimizing thermal bridges, structural adequacy aspects with respect to gravity and lateral loads, and ability to provide fire and sound breaks. In this paper a wide selection of advance framing wall assemblies is discussed in details with main focus on construction methods, architectural details with minimized thermal bridges, and structural (strength) concerns. High performance wall technologies of consideration include: double walls, Larsen truss walls, optimum or advanced framing walls, walls using distance spacers (furring) and walls made of wood-based composites. Since wood framing for wall applications is mostly used in North America, Scandinavia, and Central Europe, this study is focused on research studies from these regions. In addition, field test studies are presented discussing an application of high R-value of new and retrofitted wall assemblies in actual test houses that have been constructed and being currently monitored.

Study on the wrinkling of bulged AA 5052 alloy sheet metal during restoration

In this work, a study on the wrinkling of bulged samples of AA 5052 alloy sheets was conducted during a restoration process. Before bulging, the samples were annealed at different temperatures, i.e., at 150°C, 200°C, 250°C and 300°C. These annealed samples were then subjected to biaxial stretching (bulging) and were then compressed in between two platens. During compression (restoration), the sheet metals exhibited concentric circles of wrinkles. The aim of this research was to determine the material parameters that suppress these wrinkles. The Sheet metals that were annealed at a higher temperature exhibited a better resistance against wrinkling, because of a higher n-value, a higher R-value and a lower yield stress.

Efficacy of pea flour as an antifeedant against two stored-food mites (Acari: Acaridae) fed on dried medicinal Chinese herbs

Pea flour (Pisum sativum L.) is toxic to some stored-product pests. Botanical pesticides that contained efficient natural compounds have highlighted to be used for the control of storage mites. In the current investigation, we evaluated the effect of pea flour as an antifeedant on two stored-product mites, namely Tyrophagus putrescentiae (Schrank, 1781) and Aleuroglyphus ovatus (Troupeau, 1878) fed on two medicinal Chinese herbs: Crataegus pinnatifida Bge. var. major and Coix lachryma-jobi L. var. ma-yuen. The experiment was carried out from March to May 2012 under the optimal growth conditions of storage mites at constant temperature (25°C) and 85 ± 5% relative humidity (RH) in the dark. Pea flour was used at five concentrations (0, 0.01, 0.1, 1 and 10%). The values of LC50, LC90 and mortality of T. putrescentiae and A. ovatus were recorded at four periods (7, 14, 21 and 28 days), while their population dynamics were determined only after 21 days. The use of pea flour as an antifeedant was very efficient for the control of T. putrescentiae and A. ovatus adults. The controlling efficiency of pea flour improved due to the increase of its applied dose. The LC50 and LC90 estimates showed that pea flour was more toxic for T. putrescentiae than for A. ovatus. The concentration of 1% pea flour was responsible for more than 65% and 88% mortality of A. ovatus on C. pinnatifida and C. lachryma-jobi after 28 days, respectively. However, this concentration was sufficient to kill all individuals (100% mortality) of T. putrescentiae as the concentration of 10% pea flour. The addition of pea flour caused considerable decreases in the rate of the increase (r-value) of T. putrescentiae and A. ovatus. The highest r-values of T. putrescentiae and A. ovatus were recorded on the control treatment (0% pea flour), whereas the lowest values were observed at 1% and 10% concentrations of pea flour. The 1% concentration of pea flour is highly suggested to be used as a good and economical dose to control both of T. putrescentiae and A. ovatus on the studied Chinese herbs.

Hercynian plutonic rocks of Voras Mountain, Macedonia, Northern Greece: their structure, petrogenesis, and tectonic significance

We studied the structural, petrological, and geochemical characteristics, as well as the geotectonic setting, of the Hercynian (300 ± 3 Ma) Voras plutonic rocks intrusive into the lower part of the Pelagonian nappe pile (East Pelagonian Zone, EPZ). These rocks are compared with the neighbouring Hercynian Varnountas and Kastoria plutons intruding the tectonic upper Pelagonian part (Korabi West Pelagonian Zone, KoWPZ). Based on modal and chemical compositions, four rock-types can be distinguished for the Voras ploutonic rocks: (1) hornblende-biotite granodiorite to granite (HbBtGrd), (2) biotite granite (BtGr), (3) leucogranite (LGr), and (4) mafic microgranular enclaves (MMEs) occurring typically in HbBtGrd and BtGr. Aplites intrude HbBtGrd and BtGr whereas xenoliths are rare. The MMEs are metaluminous, while all the other rock-types are slightly peraluminous. Crystallization pressures range from 2.4 to 2.9 kbar for the HbBtGrd and 3.0 kbar for the MME. Field observations, chemical, mineralogical, and petrographical data suggest that theMME and HbBtGrd + BtGr formed as a result of a two-step evolution process. In the first step, a mantle-sourced basic magma with composition similar to the more basic MMEs fractionated (F = 0.40, 60% crystallization) and concurrently mixed with an acid magma, of composition similar to the more acid BtGr. The crystallized mineral assemblage is Qtz38.27Pl27.83Hb14.84Bt10.61Kf6.13Ap2.30Zrn0.02. The process evolved with a low r-value (r = 0.3) giving the more basic HbBtGrd. In the second step, evolved magma (more basic HbBtGrd) fractionated, while simultaneously mixing with the same acid magma, but with higher r-value (r = 0.8), giving the more evolved HbBtGrd and the BtGr after 50% crystallization (F = 0.50) to the phase assemblage Qtz30.07Pl27.75Hb5.59Bt3.33Kf23.26Tit5.86Ap1.91Zrn0.04Mt2.19. We interpret the evolution of the LGr through fractional crystallization; it formed by partial melting of gneisses or felsic charnokites and granoulites. The less evolved MME (basic end-member) had a mantle origin, whereas for the more evolved BtGr (acid end-member) we favour partial melting of gneisses or mafic charnokites. Detailed structural analysis shows a strong, polyphase Alpine deformation which affected the Hercynian Voras ploutonic rocks and is thoroughly imprinted on the host Pelagonian metamorphic basement rocks. No evidence of relict Hercynian structures has been recognized, possibly due to intense reworking by the younger Alpine deformation. We have identified five tectonic events (D1–D5) from the Late Jurassic to recent, that evolved progressively from ductile, synmetamorphic (D1, D2) to semi-ductile (D3), and finally brittle (D4, D5) conditions. Voras plutonic rocks in the EPZ, and Varnountas and Kastoria plutons in the KoWPZ, have similar major and trace element geochemistries, as well as structural evolution; they coevally intruded (Carboniferous) the Pelagonian continent as a single unit. They show similar crystallization pressures and mantle contributions for their genesis; both are related to a volcanic arc geotectonic setting, associated with the subduction of the Palaeotethys Ocean beneath the Pelagonian continental fragment, the latter possibly of Gondwana origin.

超高 <i>r</i> 値電析純鉄の変形挙動の解明

The electro-deposited pure iron has a quite sharp and isotropic 〈111〉//ND fiber texture and needle shaped grain elongated in ND. This pure iron shows the r-value over 7 and it is difficult to explain such a high r-value only from the texture. In this study the deformation behavior of the electro-deposited pure iron was investigated to reveal the mechanism of the extremely high r-value. The slip lines on the surface after the deformation indicated that the particular {110} plane slips which are parallel to ND exclusively act in the specimen. The tensile deformation by this slip system does not need the thickness decrease. Thus the limitation of the active slip system is the main cause of the extraordinary high r-value. One possibility of the limitation is the ease of the continuity of the slip plane of the adjacent grains. Because both {110} slip plane and grain boundary are perpendicular to the surface, the slip planes of adjacent grains can connect easily.

The Development of Annealing Time for Super Fine Grain and High Strength IF Steel

The hot rolling, cold rolling and simulative continuous annealing experiments were carried out in the laboratory on the base of new type SFG HSS (super fine grain, high strength steel sheet). The results show that the microstructure which contains a number of cake shaped grain can be refined and homogenized by the feasible annealing holding time. Contrast to the conventional steel, the SFG steel have the characters of super fine grain, high tensile strength, low yield strength/tensile strength rate, good elongation and high r-value high（the plastic strain ratio）．

Texture generation and implications in TWIP steels

Recrystallization of an Fe–22Mn–0.6C TWIP steel occurs by site-saturated nucleation and causes a retained rolling texture, as opposed to some literature data, in which texture randomization is reported. The present results indicate that the annealing heating rate did not significantly influence the results. Randomization might be induced by a large hot-rolled grain size and annealing twins. TWIP steels appear to have higher r-values than typical Cube-dominated face-centred cubic metals, confirming their higher deep drawing potential.

PREDICTION FOR TRAFFIC ACCIDENT SEVERITY: COMPARING THE ARTIFICIAL NEURAL NETWORK, GENETIC ALGORITHM, COMBINED GENETIC ALGORITHM AND PATTERN SEARCH METHODS

This paper focuses on predicting the severity of freeway traffic accidents by employing twelve accident-related parameters in a genetic algorithm (GA), pattern search and artificial neural network (ANN) modelling methods. The models were developed using the input parameters of driver's age and gender, the use of a seat belt, the type and safety of a vehicle, weather conditions, road surface, speed ratio, crash time, crash type, collision type and traffic flow. The models were constructed based on 1000 of crashes in total that occurred during 2007 on the Tehran–Ghom Freeway due to the fact that the remaining records were not suitable for this study. The GA evaluated eleven equations to obtain the best one. Then, GA and PS methods were combined using the best GA equation. The neural network used multi-layer perceptron (MLP) architecture that consisted of a multi-layer feed-forward network with hidden sigmoid and linear output neurons that could also fit multi-dimensional mapping problems arbitrarily well. The ANN was applied during training, testing and validation and had 12 inputs, 25 neurons in the hidden layers and 3 neurons in the output layer. The best-fit model was selected according to the R-value, root mean square errors (RMSE), mean absolute errors (MAE) and the sum of square error (SSE). The highest R-value was obtained for the ANN around 0.87, demonstrating that the ANN provided the best prediction. The combination of GA and PS methods allowed for various prediction rankings ranging from linear relationships to complex equations. The advantage of these models is improving themselves adding new data.

Investigation of thermal performance of reflective insulations for different applications

Reflective insulations are being used in home attics, flat roofs, sloped roofs and wall systems of building envelopes. The present model, hygIRC-C, was used to investigate the contribution of the reflective insulations to the thermal resistance of specimens. The predictions of the present model were compared with test data of different sample stacks with different types of reflective insulations. In a previous study, the present model was benchmarked using test data obtained from a Guarded Hot Box (GHB) in accordance with the ASTM C-1363 test method. In this study, the test data was obtained from a different test method based on the heat flow meter in accordance of ASTM C-518 in the case of horizontal sample stacks with reflective insulations. Results showed that the predicted heat fluxes on the same area and same location of Heat Flux Transducers (HFTs) on the top and bottom surfaces of the sample stacks are in good agreement with the measured heat fluxes (within ±1%). The derived R-values using these heat fluxes are also in good agreements. Due to the combined effect of heat transfer by convection and radiation in the airspace (facing the reflective surface), these predicted and measured heat fluxes are greater than the area-weighted average heat flux of whole sample stack, which is needed to determine the effective R-value of the sample. As such, the derived R-value from the test data resulted in underestimation of the effective R-value of the sample stack. After gaining confidence in the present model, it was used to conduct parametric study in order to quantify the contribution of reflective insulations to the effective R-value for a sample stack with different inclination angles, different directions of heat flow (upward and downward) and for a wide range of foil emissivity. Furthermore, the present model was used to compare the predicted R-values with the listed R-values in the 2009 ASHRAE Handbook [22] for enclosed air cavity (20 mm thick) of different effective emittance, inclinations and directions of heat flow. ► Reflective insulation is being used in roof and wall system of building envelopes. ► R-value is affected by specimen orientation, direction of heat flow and emissivity. ► Horizontal specimen with downward heat flow results in the highest R-value. ► Horizontal specimen with upward heat flow results in the lowest R-value. ► Using ASTM C-518 test method would result in underestimation of specimen R-value.

Deformation Behavior of Electro-Deposited Pure Iron with Extremely High R-Value

Electro-deposited pure iron has a quite sharp and isotropic <111>//ND fiber texture and a needle-shaped grain elongated in ND. This pure iron shows an r-value exceeding 7, which is difficult to explain from the texture alone. In this study the deformation behavior of electro-deposited pure iron was investigated to reveal the mechanism behind the extremely high r-value. The post-deformation surface slip lines indicated that the particular <110> plane slips, which are perpendicular to ND, exclusively act in the specimen. The tensile deformation caused by this slip system does not require any decrease in thickness, hence the extraordinary high r-value is mainly attributable to this limitation of the active slip system. Presumably, the needle-shaped microstructure affected the limitation of the slip system.

Texture Control of Aluminum and Magnesium Alloys by the Symmetric/Asymmetric Combination Rolling Process

In order to develop favorable textures for deep drawing of Al-Mg-Si and Mg-Al-Zn alloys that are promising as automotive body panels, we have adopted the symmetric/asymmetric combination rolling (SACR) process consisting of conventional symmetric rolling and subsequent asymmetric rolling at relatively low reduction. The combination of symmetric cold rolling and asymmetric warm rolling for AA6022 sheets leads to the formation of “TD-rotated β-fiber texture”, resulting in the evolution of {111} recrystallization texture after solution treatment at a high temperature. The SACR processed and solution-treated sheets show a high average r-value with small in-plane anisotropy, and consequently the limiting drawing ratio increases significantly, compared to that of the cold-rolled and solution-treated sheets. In the case of AZ31 magnesium alloy, the SACR process by hot rolling causes the formation of a unique texture, which shows two (0001) poles with tilt angles of 0 and −40 degrees from the normal direction (ND) toward the rolling direction (RD). In addition, subsequent annealing weakens intensity of the double-peak texture, so that the drawability is greatly improved in comparison with that of the conventional warm-rolled sheets with a strong basal texture. At the same time, yield strength decreases to some extent, but the SACR processed and annealed sheets exhibit a good balance of strength and formability due to a mixed texture with basal and tilt components.

The Study on the Low Yield Strength for Super Fine Grain and High Strength Bearing Nb if Steel

The cold rolling and simulative continuous annealing experiments after rolling were carried out in the laboratory on the base of super fine grain (SFG) steel sheet. The microstructure and the second-phase particles precipitated behavior were analyzed by the technology of OM, TEM and EDX. It is found that the fined Nb(C, N) can be formed by adding micro-alloy element Nb. It is noted that the yield strength is low as well as the tensile strength is high by the PFZ which is free of precipitate called precipitated free zone on the one side of the grain boundary. Contrast to the conventional IF steel, the super fine grain steel has super fine grains and gives excellent press-formability such as low yield strength, high r-value（the plastic strain ratio）. High strength cold-rolled steel sheets (HSS) with high formability have been developed in the last decade, in which the major strengthening method was solid-solution hardening with silicon, manganese and phosphorous [1-3]. When the IF steel is strengthened with the high amount of solid-solution elements, it becomes susceptible to the secondary work embrittlement because of the lack of grain boundary strength [4-6]. In this paper, High strength cold-rolled steel sheets (HSS) with high formability have been developed for the IF steel-bases. The grain refinement and precipitation hardening are achieved by means of the fine distribution of carbide under the appropriate combination of the relatively higher carbon content near 0.0070 mass% with niobium. As the result, this type of IF-HSS has been successfully developed to reach a higher r-value as compared with the conventional IF-HSS.

Yields and nutrient pools in soils cultivated with Tectona grandis and Gmelina arborea in Nigerian rainforest ecosystem

This study examined the yield of the two most prominent exotic species in southwest Nigeria and the nutrient status of soils cultivated with these species. The impacts of plantation development on soil nutrients were also examined. The plantations species are Gmelina arborea (Gmelina) stands established in 1984, 1988, 1990 and 1994 and Tectona grandis (Teak) established in 1990, 1992, 1994, 1996 and 1997. Growth data and composite soil samples from 3 depths (0–15, 15–30 and 30–60 cm) were collected from five equal sized plots (20 × 20 m 2) randomly located in the plantation of the two species. Also, soil samples were collected from the adjacent natural forest for comparison. The results for both species show that tree growth variables increased substantially with increase in tree age. There was significant difference in number of trees per hectare, dominant diameter, volume/ha and MAI for the Gmelina stands. In the Teak stand, there was significant difference in most of the tree growth variables also. Nutrients required by plants to survive were present in the soil samples from the plantations and the natural forest in different proportions. There was high correlation between percentage sand and most of the tree growth variables for both species. The pH value obtained for the Gmelina stands ranged between 6.47 and 7.47 while that of Teak stands ranged between 5.57 and 8.33. There was also a high and positive relationship between some soil chemical properties and tree growth variables. The highest significant correlation coefficient existed between phosphorus concentration and basal area for stands of both species. The r-values are 0.98 and 0.96 for Gmelina and Teak, respectively. While a high, negative and significant r-value (−0.88) was also obtained between potassium and volume/ha for the Gmelina stands, a high positive r-value was obtained between the potassium and basal area for the Teak stands. Comparison of soil nutrients in the plantations with the nutrients in the natural forest revealed the adverse impacts of plantation establishment on soil nutrient status. Recommendations on land policy issues and forest conservation were made.

Pronival rampart formation in relation to snow-avalanche activity and Schmidt-hammer exposure-age dating (SHD): Three case studies from southern Norway

Pronival (protalus) ramparts at three sites in southern Norway—Smørbotn, Alnesreset and Nystølsnovi—are assessed in relation to evidence of snow-avalanche activity, and dated using Schmidt-hammer exposure-age dating (SHD). The position of each rampart suggests frequent snow avalanches played a major role in rampart formation. The pronival ramparts at Smørbotn and Nystølsnovi are characterized by a high proportion of unweathered, very angular clasts, many clean boulders (without any lichen or moss cover), steep distal slope angles, and a disturbed ground cover of vegetation with characteristic alpine pioneer plant species on crests and proximal slopes. High Schmidt-hammer R-values (mean 56.2–58.5) yielded SHD ages of <2900years and <1550years, respectively. These ramparts are currently active and have probably developed since the early Holocene under environmental conditions similar to those at present. Pronival ramparts at Alnesreset are characterized by highly weathered, mainly angular boulders (virtually none of which is clean), a mature, undisturbed vegetation cover, and lower distal slope angles. Mean R-values of 39.9–40.3 from these ramparts yielded SHD ages within the range 9450 to 14,650years (with 95% certainty), indicating formation during the Younger Dryas Stadial and relict status for most of the Holocene. Our results: (1) show that rockfall is not the only primary process involved in the formation of pronival ramparts; (2) broaden the range of landforms included in snow-avalanche geomorphology; (3) demonstrate the feasibility of dating pronival ramparts; and (4) indicate their potential in palaeoenvironmental reconstruction.

A new dataset evaluation method based on category overlap

The quality of dataset has a profound effect on classification accuracy, and there is a clear need for some method to evaluate this quality. In this paper, we propose a new dataset evaluation method using the R-value measure. This proposed method is based on the ratio of overlapping areas among categories in a dataset. A high R-value for a dataset indicates that the dataset contains wide overlapping areas among its categories, and classification accuracy on the dataset may become low. We can use the R-value measure to understand the characteristics of a dataset, the feature selection process, and the proper design of new classifiers.

Effect of Texture on r-value of Ferritic Stainless Steel Sheets

The effects of cold rolling texture on the formation of recrystallization texture and the relationship between recrystallization texture and r-value were investigated for sheets of titanium-stabilized extra-high purity Type 436L and Type 409L ferritic stainless steels. The recrystallization texture and average r-value were affected by the cold rolling texture. Annealed sheets with a sharp γ-fiber texture and very high average r-values were obtained from cold-rolled sheets with a strong γ-fiber texture (Type A). On the other hand, the {h,1,1} fiber texture developed from cold-rolled sheets with a strong α-fiber texture (Type C). In terms of the relationship between {111} intensity and the average r-value, chromium content had less effect than the cold rolling texture. The planar anisotropies of r-values and the average r-values of Type 436L and 409L sheets with Type A cold rolling textures agreed well with those calculated from the textures in the center layers by using the relaxed-constraints model and the CRSS ratio τc{211}/τc{110} of 1.1. On the other hand, for the sheets with Type C cold rolling textures and a marked texture gradient, it was necessary to consider the texture gradient in the thickness direction. The texture inhomogeneity by the orientations other than {111} texture affected the relationship between {111} intensity and average r-value.

Synthesis, characterization of poly(4, 4’-diaminophenylethanepyromellitimide) and its use as immobilized enzyme polyimide membrane

A novel polyimide prepared from pyromellitic dianhydride (PMDA) and 1,2-bis(4-aminophenyl)ethane was characterized by Fourier transform infrared spectrometer and gel permeation chromatography. Thermal properties of the poly(4,4’-diaminophenylethane-pyromellitimide) (PDP) were evaluated by differential scanning calorimetry, differential thermal analysis and thermogravimetry. The PDP exhibited high decomposition temperature Td (°C), good thermal stability and good adhesive properties. Moreover, that the possibility of whether the chemically-prepared polyimide film could be used as a membrane for immobilization of glucose oxidase (GOx) was investigated. The amperometric response of the PDP/GOx/Pt electrode to hydrogen peroxide, formed as the product of enzymatic reaction, was measured at a potential of 700 mV (vs. SCE) in phosphate buffer solution by means of the TB technique. The amperometric glucose sensor was very high R-value (0.9995). The structure of the GOx micelles contained in polyimide membrane was observed by scanning electron microscopy. From the amperometric responses, it was also demonstrated that PDP film could be used as a solid-state immobilized enzyme polyimide membrane for biosensor design because of its strong adherence to electrode surface and chemical stability.

Effect of Hot Band Annealing Processes on Microstructure, Texture and r-Value of Ferritic Stainless Steel

The effect of hot band annealing processes, namely simulating batch annealing and continuous annealing, on microstructure, texture, grain boundary character and r-value of ferritic stainless steel was investigated. The hot band displayed a highly elongated ribbon-like structure and a pronounced deformation texture. The fully recrystallized grains were observed after continuous annealing while the “typical” hot rolled structure was remained after batch annealing. Also, the α-fibre texture formed during hot rolling almost disappeared after continuous annealing and a weak γ-fibre texture was obtained. By contract, the α-fibre texture remained very stable after batch annealing. After cold rolling and recrystallization annealing, the favorable γ-fibre texture was achieved in the continuous annealed steel. Instead of forming the γ-fibre texture, the recrystallization texture was notably shifted toward {223}<582> in the batch annealed steel. Finally, the improvement in drawability with high r-value and low Δ r-value were also displayed in sheet through the initial continuous annealing process.

An analysis of wrinkling limit diagrams of aluminum alloy 5005 annealed at different temperatures

This paper deals with the wrinkling limit diagrams for Aluminum alloy 5005 sheets having thickness of 2.00 mm annealed at four different temperatures namely 200°C, 300°C, 400°C and 500°C. The study pertains to deep drawing into cylindrical cups through conical die using a flat bottom punch. It is proved by these researchers and others that the onset of wrinkling takes place when the ratio of strain increments (der / deθ) or the ratio of strain (er / eθ) reaches a critical value during the drawing process. These values which could be determined experimentally over which the wrinkling takes place, is shown in the form of wrinkling limit diagrams for the above grade at different annealing temperature. An attempt is also made to develop the wrinkling theory that predicts the wrinkling based on results obtained in the form of wrinkling limit diagrams established for the above grade at different annealed temperature. Further it has been observed from the stress ratio that there is a clear curve, that separates the region from safe and the wrinkling region. Further it was observed that the annealed sheets having high n-value, high R-value and high UTS /σy ratio improve the resistance against wrinkling.