Creep Area Research Articles

Nonlinear damage creep model based on variable-order fractional theory for rock materials

In this study, based on the variable-order fractional theory and continuous damage model with sum function, we proposed a nonlinear variable-order fractional damage creep model to describe the creep mechanical behavior of rock materials. For better exhibiting the evolution of consumption of viscosity in creep, the ‘two-area-continuous-variable-order-analytical-method’ is first presented. In different areas of creep (area 1 and 2), the consumption of viscosity in each area is expressed by the varying-order with an exponential function. The consumption of viscosity mainly happens in the area 1 within decaying and steady creep and most of viscosity is consumed to resist deformation of creep. And with the development of time, the proportion of consumption of viscosity in material gradually decreases, which is same as variation of order. During the area 2, comparing to the consumption of viscosity in the area 1, the viscosity play a relatively weak role in resisting deformation of creep, which is due to plasticity occupy the mail role. Finally, for verifying the applicability and rationality of proposed variable-order fractional damage creep model, except for experimental creep data of sandstone in this work, additional creep data of salt rock and mudstone are also achieved from other papers. The fitting curves of proposed model are well agreement with experimental data.

Теплостійкість іонноазотованих алюмінієвих сплавів при ізотермічному та термоциклічному впливі

Тhe study of the main parameter that limits the use of pistons made of aluminum alloys in boosting engines - heat resistance and its dependence on diffusion ion-nitrided layers. In the analysis of recent studies and publications, the most common methods of heating samples during tests, their advantages and disadvantages are identified. The task of the study is to identify the relationship of factors that determine the heat resistance of ion-nitrided aluminum alloys under isothermal and thermocyclic effects for effective analysis of the mechanism of phenomena and control of the technological process of strengthening the pistons. The availability of this information will increase the strength and reliability of both the coatings themselves and the parts with coatings at the stage of their design. A set of laboratory equipment based on the Nutcracker installation was used for the study, which provides cyclic change of temperature and load of the sample, control and recording of temperature values, loading and deformation and operation in automatic mode. Flat samples of aluminum alloy AL2I with heat-protective diffusion ion-nitrided layers applied in the VIPA-1 installation and samples without treatment were used. Characteristics of the thermal cycle: 500 ° C ↔ 720 ˚C. heating time - 10 sec., cooling 15 sec., which corresponds to the real operating conditions of the pistons. The fixed value of the load was 0.8σВ according to DSTU 2637-94 and the criteria for determining the allowable stress in the Standards of ASME (80% of the average value of stresses that lead to a total deformation of 1%). The curves of isothermal and thermocyclic creep having three clearly expressed sites of creep are defined, depending on temperature their duration is different. Isothermal and thermocyclic creep curves of aluminum alloy AL21 with heat-protective diffusion ion-nitrided layers have three distinct creep areas, depending on the temperature their duration is different. This is due to the presence in the surface layer of the reinforcing phase AlNi; uniformity of distribution of components of a covering on a surface and degree of their refractoryness. This is due to the complexity of the movement of dislocations, which on their way face the need to overcome large obstacles in their movement, caused by the presence of a reinforced layer. Conclusions. Based on the obtained curves of isothermal and thermo cyclic creep, it is established that the type of creep curves depends on the temperature and conditions of its influence on the composition "base-coating"; the time to failure in the thermo cyclic test mode is less than in the isothermal; in the process of creep of aluminum alloy AL21 with heat-protective diffusion ion-nitrided layers, two competing processes are observed: hardening due to plastic deformation and removal of hardening under the influence of elevated temperature; despite the different composition of heat-protective diffusion ion-nitrided layers, the resistance to isothermal and thermo cyclic creep of the reinforced aluminum alloy AL21 increased by 1.8 ... 2.2 times.

Effects of Farrowing Stall Layout and Number of Heat Lamps on Sow and Piglet Production Performance.

Simple SummaryIn the commercial swine industry, farrowing stalls are commonly used as a strategy to reduce piglet pre-weaning mortalities caused by sow over-lay. Farrowing stall dimensions have generally remained the same over the past 50 years in the United States, even though the sizes of both the sows and litters have increased considerably. This extensive field study investigated if sow and piglet productivity would be affected when housed in stalls of traditional layout, additional area for the piglets, or additional area for the sow. All three layouts were also tested with use of one or two supplementary heat lamps in the creep area. Results show that stall layout and number of heat lamps had no statistical impact on production outcomes. However, seasonal differences, sow parity, and number of litter mates did have significant effects. Providing larger stalls or an additional heat lamp costs more for the producer but did not yield production improvements. Most farrowing facilities in the United States use stalls and heat lamps to improve sow and piglet productivity. This study investigated these factors by comparing production outcomes for three different farrowing stall layouts (traditional, expanded creep area, expanded sow area) and use of one or two heat lamps. Data were collected on 427 sows and their litters over one year. Results showed no statistical differences due to experimental treatment for any of the production metrics recorded, excluding percent stillborn. Parity one sows had fewer piglets born alive (p < 0.001), lower percent mortality (p = 0.001) and over-lay (p = 0.003), and a greater number of piglets weaned (p < 0.001) with lower average daily weight gain (ADG) (p < 0.001) and more uniform litters (p = 0.001) as compared to higher parity sows. Farrowing turn, associated with group/seasonal changes, had a significant impact on most of the production metrics measured. Number of piglets born influenced the percent stillborn (p < 0.001). Adjusted litter size had a significant impact on percent mortality (p < 0.001), percent over-lay (p < 0.001), and number of piglets weaned (p < 0.001). As the number of piglets weaned per litter increased, both piglet ADG and litter uniformity decreased (p < 0.001). This information can be used to guide producers in farrowing facility design.

Alternative light colors in suckling piglet creep area: preference and validation tests in swine maternity

ABSTRACT: We performed a two-stage experiment: a preference and a validation test in swine litters, to determine whether suckling piglets preferred alternative light colors in their creep area over white light; we also determined whether the preferred color affected piglet behavior. In the first stage, five trials of two consecutive days were performed, each at 21-day intervals. In each trial, 40 piglets, from three to five days old, from four F1 sows (Large White x Landrace), were distributed in four treatments, in a paired scheme, receiving the following treatments: Treatment GR: white light vs. green light ; Treatment BL: white light vs. blue light; Treatment YE: yellow light vs. white light; Treatment RD: white light vs. red light. For the validation test, three consecutive lots of eight F1 sows (Large White x Landrace) and their corresponding maternity were used, remaining from birth under the influence of treatments T_Gr and T_Wh, totaling three replicates. T_Gr corresponded to four creep areaswith green LED light and T_Wh to four nurseries with white LED light. The piglets showed a significant preference only for white over blue. Among the alternative colors, piglets significantly preferred green. In the validation stage, there was no significant effect of colors on the mean percentage of permanence of the piglets inside the creep areas over all evaluated periods. Piglets between two and five days of age prefer green lighting;however,in the creep area, the light color used did not influence piglet behavior.

Pilot-Scale Assessment of a Novel Farrowing Creep Area Supplementary Heat Source.

Simple SummaryPre-weaning mortality (PWM) causes major economic and productivity losses for the US swine industry. This pilot-scale study evaluated a novel semi-enclosed heated microclimate (SEHM) as a supplementary heat source for farrowing creep areas. Six farrowing cycles (from January to July 2019) were studied in two rooms with 24 farrowing stalls per room. Six SEHMs (each SEHM covers two stalls) were randomly distributed in each room and compared to heat lamps (HLs) for productivity and electricity usage. Data were collected on 113 (SEHM) and 101 litters (HL), and there was no statistically significant difference for average daily gain and weaning weight. There was a tendency for significance of PWM (p = 0.08). A significant difference (p = 0.02) was noted in the PWM attributed to over-lay mortalities, SEHM = 4.05% (± 0.76%) compared to HL = 6.04% (± 0.78%). The SEHM averaged 3.25 kWh d−1 (2.91, 3.59 kWh d−1; 95% CI), which was significantly different (p < 0.01) from the HL equivalent with 125 W bulbs (6 kWh d−1). Based on only electrical savings, payback was estimated at 74 farrowing cycles, or at 12 cycles y−1, 6.1 years. The SEHM demonstrated promising pilot-scale results for increasing productivity and decreasing electricity usage compared to conventional HLs.Pre-weaning morality (PWM) is attributed to a poor creep area microclimate and causes major economic and productivity losses for the US swine industry. Piglets need supplementary heat to overcome a high surface area to body weight ratio and minimal thermoregulation. A pilot-scale study was conducted to evaluate a semi-enclosed heated microclimate (SEHM) as a supplementary heat source for farrowing creep areas over six farrowing cycles (from January to July 2019) in two rooms with 24 farrowing stalls in each room. Six SEHMs (each SEHM covers two stalls) were randomly distributed to each room and compared to heat lamps (HLs) for productivity and electricity usage. Data from 113 (SEHM) and 101 litters (HL) showed no significant difference between treatments in average daily gain (p = 0.26), 252.4 ± 8.0 g hd−1 d−1 (SEHM) and 260.3 ± 8.1 g hd−1 d−1 (HL) and PWM (p = 0.08), 9.67% ± 0.82% (SEHM) and 12.04% ± 0.87% (HL). However, a significant difference (p = 0.02) was noted in the PWM attributed to over-lay mortalities, 4.05% ± 0.76% (SEHM) compared to 6.04% ± 0.78% (HL). The SEHM electricity averaged 3.25 kWh d−1 (2.91, 3.59 kWh d−1; 95% CI), which was significantly different (p < 0.01) from the HL equivalent (125 W bulb; 6 kWh d−1).

In Situ Creep Behavior Characterization of Single Crystal Superalloy by UV-DIC at 980 °C

High temperature creep resistance is a critical characteristic of Ni-based single crystal (SX) superalloys. In this work, the creep behavior of a Ni-based SX superalloy was in situ characterized at 980 °C by ultraviolet (UV) imaging combined two-dimensional digital image correlation (DIC) in vacuum environment. The surface pattern was fabricated to maintain stable over 65 h at 980 °C. The pattern images captured by UV imaging were analyzed using mean gray value and the full-field strain map of creep deformation was obtained. A laser displacement senor (LDS) was employed for measuring the creep strain on the specimen for comparison. The creep deformation result shows a good agreement between DIC and LDS, the microstructure of the different creep areas on the specimens also demonstrate that the results of DIC are reliable. The in situ creep characterization by UV-DIC shows a great potential for investigating creep behaviors at high temperatures.

Twist static friction and creep between UHMWPE and bovine skin for human exoprosthesis

The twist static friction and the creep behavior of bovine skin in contact with Ultra High Molecular Weight Polyethylene (UHMWPE) indenters were studied by employing both theoretical and experimental methods. Loads (1 and 2 N) were applied to bovine skin using different indenter shapes. Moreover, the creep area and the coefficient of static friction were also discussed and analysed for different time durations. The experimental and theoretical results showed that the Voight-Kelvin rheological model could be used to represent the mechanical response of the cattle skin. As a conclusion, the creep parameter and the coefficient of static friction of bovine skin increased in time. For the circular indenter, the creep area was higher than in the case of the other shapes.The study provides a base for more investigations on cattle skin behavior in order to be utilized on a rigid support (UHMWPE) as a new solution for “exoprosthesis support”.

Numerical Simulation on Creep Process of Surrounding Rock in Soft Rock Tunnel

It is obvious that creep is one of important characteristics of surrounding rock in soft rock tunnel. There was less study on creep process of surrounding rock in the past which affected the engineer's judgment to long term stability of tunnel seriously. In this paper, the Cvsic model is selected and its parameters are determined based on soft rock creep test results, furthermore, the software FLAC3D was used to analyze the viscoelastic plastic creep process of surrounding rock in soft rock roadway. The results show that: the maximum creep rate occurs at the moment when the soft rock tunnel is excavated , then the creep rate decreases and finally evolves into steady creep; it will initially form a creep zone in the tunnel surface and then the deep surrounding rock will also form a damage zone by stress adjustment, forming a larger creep area; hoop stress decreases while the radial stress increases gradually from the surface to the deep rock mass of roadway, and eventually both will approach to the initial in-situ stress ; The plastic zone will gradually expand after the excavation of viscoelastic-plastic tunnel and tend to be stable when reaches to the steady creep stage. The hoop stress on the border between elastic and plastic zone of the surrounding rock reaches to peak stress; the deformation of surrounding rock changes suddenly and the deformation rate, the area of plastic zone increase with the increase of moisture content in the process of creep.

Radiant heat increases piglets’ use of the heated creep area on the critical days after birth

The aim of the present study was to investigate how piglets’ use of a creep area is affected by using radiant heat compared to an incandescent light bulb. It was hypothesised that radiant heat would increase the use of the creep area. Twenty litters were randomly assigned to one of two heat sources in the creep area: (1) an incandescent light bulb (STANDARD, n=10) or (2) a radiant heat source (RADIANT, n=10) with five of each type of heat source in each of two batches. Observations on piglets’ position in the pen were made by scan sampling every ten minutes in a 4-hour period from 1100 to 1500h on day 1–7, 14 and 21 post partum. A higher percentage of piglets in the creep area was seen for RADIANT litters compared to STANDARD litters on day 2 (P=0.002) and day 3 (P=0.005), and percentage of piglets in the creep area increased for RADIANT litters from day 1 to 2 (P<0.001) and from day 2 to 3 (P=0.03) while it first increased for STANDARD litters from day 2 to 3 (P=0.01). In conclusion, radiant heat gave an earlier and increased use of the creep area on the critical days after birth.

From the seismic cycle to long-term deformation: linking seismic coupling and Quaternary coastal geomorphology along the Andean megathrust

Measurement of interseismic strain along subduction zones reveals the location of both locked asperities, which might rupture during Megathrust earthquakes, and creeping zones, which tend to arrest such seismic ruptures. The heterogeneous pattern of interseismic coupling presumably relates to spatial variations of frictional properties along the subduction interface and may also show up in the forearc morphology. To investigate this hypothesis, we compiled information on the extent of earthquake ruptures for the last 500 years and uplift rates derived from dated marine terraces along the South American coastline from central Peru to Southern Chile. We additionally calculated a new interseismic coupling model for that same area based on a compilation of GPS data. We show that the coastline geometry, characterized by the distance between the coast and the trench, the latitudinal variations of long-term uplift rates and the spatial pattern of interseismic coupling are correlated. Zones of faster and long-term permanent coastal uplift, evidenced by uplifted marine terraces, coincide with peninsulas, and also with areas of creep on the megathrust where slip is mostly aseismic and tend to arrest seismic ruptures. We conclude that spatial variations of frictional properties along the megathrust dictate the tectono-geomorphological evolution of the coastal zone and the extent of seismic ruptures along strike.

Sow and piglet behavioral associations in farrowing pens with temporary crating and in farrowing crates

The farrowing system in which a sow and her piglets are housed may influence the manner in which they interact with one another. Behavioral displays of sows in farrowing crates are limited, whereas pen-based alternatives to farrowing crates enable a greater range of behavioral expression, including interacting more with piglets. The associations between sow behavior and piglet behavior in crates and pens with temporary crating were compared using 2 different data sets. During days 1-6 after farrowing, 15 sows and their litters were observed in farrowing crates, and 16 sows and their litters were observed in pens with temporary crating. Sows in farrowing crates were crated throughout days 1-6, and sows in pens were crated during days 1-3 (period 1) and loose in the pen on days 4-6 (period 2). Additionally, gilts and their litters were observed during the first 3 days after farrowing. Gilts were either born and reared in farrowing crates (C) or in a pen with temporary crating (P) and were observed after they farrowed in either a farrowing crate or in a pen with temporary crating. Hence, there were 4 experimental groups of gilts: CC (born and reared in a crate, farrowed in a crate, N = 8), CP (born and reared in a crate, farrowed in a pen, N = 6), PC (born and reared in a pen, farrowed in a crate N = 5), and PP (born and reared in a pen, farrowed in a pen, N = 8). When sows and gilts were standing, piglets were mostly inactive in the creep area. When they were lying, piglets were inactive either in the creep, or at the sow's udder. Piglets in pens spent more time inactive at the sow's udder than piglets in crates when the sow was lying in period 1, and in period 2, when penned sows were loose (P < 0.01). Piglets tended to be active when sows and gilts touched, investigated, and vocalized toward them. Piglets of gilts that were born and reared in pens and farrowed in pens (PP) vocalized more toward their dam than those in CC, CP, and PC groups, particularly when their dam was vocalizing toward them (P < 0.01), investigating them (P < 0.01), and touching them (P < 0.01). The present study demonstrated that some associations between sow and piglet behavior changed when the sow was no longer confined in a crate. Furthermore, the piglets of gilts born and reared in a farrowing system that did not match the environment they later farrowed in may be influenced by their dam's adaptation to an unfamiliar environment.

IMPROVING THE RELIABILITY OF THE PISTON OF HIGH-SPEED DIESEL BOOSTED

The problem of a piston reliability ensuring in the high-power diesel engine service and specifically the tear in particular areas of the piston skirt is discussed in the paper. The creep process and stress relaxation simulation for aluminium silicon alloy Al-25 is performed. The alloy creep threshold in a short-time term is ascertained. The material creep area on the piston surface is determined. The approach for tear elimination in the investigated area is suggested.

The performance and behaviour of gilts and their piglets is influenced by whether they were born and reared in farrowing crates or farrowing pens

The level of maternal care experienced by offspring in early life may influence their future behaviour. If maternal behaviour is influenced by the level of mother-young interaction in early life, this may persist in subsequent generations through altered maternal behaviour of female offspring. In the present study, post-farrowing behaviour of gilts and their piglets was observed in a crossover experiment. Gilts were born and reared in a farrowing crate (C) or in a pen with temporary confinement (P); and were observed after they farrowed in a crate or a pen with temporary confinement. Hence there were four experimental groups: CC (born and reared in a crate, farrowed in a crate, N =8), CP (born and reared in a crate, farrowed in a pen, N =6), PC (born and reared in a pen, farrowed in a crate N =5), and PP (born and reared in a pen, farrowed in a pen, N =8). Gilts and their piglets were observed for the first three days post-farrowing whilst they were all confined in crates. There were no differences between groups for total born, born alive, weaned per litter, or piglet mortality. Gilts in the PP group interacted more with neighbouring gilts/sows than any other (P<0.05). Gilts born and reared in pens touched their piglets more (Pborn =0.02) and vocalised more towards their piglets (Pborn = 0.01) than gilts born and reared in farrowing crates. Piglets born to PP gilts spent more time active in the creep area compared to all other groups (P<0.05). The current study demonstrated that the expression of some piglet-directed behaviour was influenced by the system in which a gilt was born and reared.

Fracture-based correlation of uniaxial and small punch creep data

A critical problem of small punch test is determining the relation between this test and the conventional uniaxial test. In high-temperature creep conditions studied by constant-force variant of small punch test, this problem is often approached empirically by comparing force in small punch test and the applied stress in conventional creep test of the same duration, i.e. of the same time to fracture. A different approach is used in the evaluation of constant-rate small punch test: the force is normalized by the square of specimen thickness or, recently, by the product of the specimen thickness and a relevant deflection. Modifications of this advanced approach in the creep area are examined in the present paper. The deflection observed at fracture of specimen in small punch creep test is taken as a starting normalization quantity. The suggested correlations are illustrated by means of data obtained by creep testing of steels usually employed in power plants (P91, P92) or proposed for heavy-duty service (Eurofer’97).

Planimetric measurement as a method for scientific assessment of space requirements of young suckling piglets in the creep area

In recent years, litter sizes of pigs have continuously increased. In modern pig production, litters with up to 15 or even more piglets born alive are no longer an exception. However, the size of heated creep areas, in which the piglets can retire to rest, has not yet been adapted to the increasing number of piglets per litter. Therefore, the objective of this study was to determine the space requirements of piglets lying in a creep area in order to assess whether common sizes of creep areas are still sufficient to accommodate all piglets of a litter. Thus, the exact floor space that suckling piglets of different weight classes occupied due to their physical size and shape was measured automatically using the colour contrast planimetric method “KobaPlan”. A total number of 234 images of piglets from 0.5kg to 6kg was taken from top view in a special planimetric box. In the digital photo, the number of animal associated pixels was counted by the “KobaPlan” software and compared to a reference area. Thus, the area covered by the individual piglet was calculated. Thereby, it was possible to determine the space the piglets dissipated in lateral and ventral recumbent positions up to the age of three weeks. The results revealed that the space requirements of piglets increased linearly with their weights, independent of lying position. The mean floor space covered by piglets weighing 0.5–1.5kg lying on their bellies was 249±42cm2, and piglets lying in lateral position covered 275±33cm2. Piglets weighing 3.0–4.5kg covered more space than lower weight classes in ventral (554±68cm2) and lateral positions (502±41cm2). Piglets in the heaviest weight class (4.5–6.0kg) required 633±52cm2 when lying in a lateral position. Assuming that all piglets were lying in lateral recumbency, for a litter size of 12 piglets weighing up to 6.0kg, a space requirement of 0.76m2 was calculated. For 14 piglets, an area of 0.9m2, and for 16 piglets 1.01m2 is needed. Bearing in mind that litter sizes are growing, a creep area of approximately 0.9m2 is recommended for piglets up to three weeks of age based on a space requirement of 0.06m2 per piglet.

A ROBUST REGISTRATION ALGORITHM FOR POINT CLOUDS FROM UAV IMAGES FOR CHANGE DETECTION

Landslides are among the major threats to urban landscape and manmade infrastructure. They often cause economic losses, property damages, and loss of lives. Temporal monitoring data of landslides from different epochs empowers the evaluation of landslide progression. Alignment of overlapping surfaces from two or more epochs is crucial for the proper analysis of landslide dynamics. The traditional methods for point-cloud-based landslide monitoring rely on using a variation of the Iterative Closest Point (ICP) registration procedure to align any reconstructed surfaces from different epochs to a common reference frame. However, sometimes the ICP-based registration can fail or may not provide sufficient accuracy. For example, point clouds from different epochs might fit to local minima due to lack of geometrical variability within the data. Also, manual interaction is required to exclude any non-stable areas from the registration process. In this paper, a robust image-based registration method is introduced for the simultaneous evaluation of all registration parameters. This includes the Interior Orientation Parameters (IOPs) of the camera and the Exterior Orientation Parameters (EOPs) of the involved images from all available observation epochs via a bundle block adjustment with self-calibration. Next, a semi-global dense matching technique is implemented to generate dense 3D point clouds for each epoch using the images captured in a particular epoch separately. The normal distances between any two consecutive point clouds can then be readily computed, because the point clouds are already effectively co-registered. A low-cost DJI Phantom II Unmanned Aerial Vehicle (UAV) was customised and used in this research for temporal data collection over an active soil creep area in Lethbridge, Alberta, Canada. The customisation included adding a GPS logger and a Large-Field-Of-View (LFOV) action camera which facilitated capturing high-resolution geo-tagged images in two epochs over the period of one year (i.e., May 2014 and May 2015). Note that due to the coarse accuracy of the on-board GPS receiver (e.g., +/- 5-10 m) the geo-tagged positions of the images were only used as initial values in the bundle block adjustment. Normal distances, signifying detected changes, varying from 20 cm to 4 m were identified between the two epochs. The accuracy of the co-registered surfaces was estimated by comparing non-active patches within the monitored area of interest. Since these non-active sub-areas are stationary, the computed normal distances should theoretically be close to zero. The quality control of the registration results showed that the average normal distance was approximately 4 cm, which is within the noise level of the reconstructed surfaces.

A ROBUST REGISTRATION ALGORITHM FOR POINT CLOUDS FROM UAV IMAGES FOR CHANGE DETECTION

Abstract. Landslides are among the major threats to urban landscape and manmade infrastructure. They often cause economic losses, property damages, and loss of lives. Temporal monitoring data of landslides from different epochs empowers the evaluation of landslide progression. Alignment of overlapping surfaces from two or more epochs is crucial for the proper analysis of landslide dynamics. The traditional methods for point-cloud-based landslide monitoring rely on using a variation of the Iterative Closest Point (ICP) registration procedure to align any reconstructed surfaces from different epochs to a common reference frame. However, sometimes the ICP-based registration can fail or may not provide sufficient accuracy. For example, point clouds from different epochs might fit to local minima due to lack of geometrical variability within the data. Also, manual interaction is required to exclude any non-stable areas from the registration process. In this paper, a robust image-based registration method is introduced for the simultaneous evaluation of all registration parameters. This includes the Interior Orientation Parameters (IOPs) of the camera and the Exterior Orientation Parameters (EOPs) of the involved images from all available observation epochs via a bundle block adjustment with self-calibration. Next, a semi-global dense matching technique is implemented to generate dense 3D point clouds for each epoch using the images captured in a particular epoch separately. The normal distances between any two consecutive point clouds can then be readily computed, because the point clouds are already effectively co-registered. A low-cost DJI Phantom II Unmanned Aerial Vehicle (UAV) was customised and used in this research for temporal data collection over an active soil creep area in Lethbridge, Alberta, Canada. The customisation included adding a GPS logger and a Large-Field-Of-View (LFOV) action camera which facilitated capturing high-resolution geo-tagged images in two epochs over the period of one year (i.e., May 2014 and May 2015). Note that due to the coarse accuracy of the on-board GPS receiver (e.g., +/- 5-10 m) the geo-tagged positions of the images were only used as initial values in the bundle block adjustment. Normal distances, signifying detected changes, varying from 20 cm to 4 m were identified between the two epochs. The accuracy of the co-registered surfaces was estimated by comparing non-active patches within the monitored area of interest. Since these non-active sub-areas are stationary, the computed normal distances should theoretically be close to zero. The quality control of the registration results showed that the average normal distance was approximately 4 cm, which is within the noise level of the reconstructed surfaces.

Summer Legumes for Creep Grazing in Cow-Calf Production on Bermudagrass Pastures

The extensive cow-calf industry in the Gulf Coast Region of the southeastern USA is based on pastures of warm-season perennial grasses, which often provide insufficient forage availability and/or nutritive value in late summer. Several species of summer-growing legumes have potential to increase nutrient availability for nursing calves through creep grazing. Selected warm-season legumes were evaluated at multiple locations across Louisiana. At each location, a treatment with 10% of the pasture area planted to legume was compared to a bermudagrass control treatment. Objectives were to assess both plant and animal factors influencing potential for creep grazing to increase calf weaning weight. Iron-and-Clay cowpea was widely adapted and suited to grazing defoliation although not tolerant of flooding. Aeschynomene was particularly well adapted to silt loam and silty clay loam bottomland soils but was not readily grazed when woody stems developed before stocking. Calves had to learn to utilize creep areas and consume unfamiliar legume species. Both pasture and animal characteristics affected response to legume creep grazing. At the Hill Farm Research Station, the combination of young cows and pastures with limiting nutritive values produced low weaning weights (200 to 215 kg) and resulted in weaning weight increases of from 5 to 7 kg from creep grazing. Benefits were not detected from creep grazing at other locations where calf weaning weights were higher. Creep grazing can contribute to calf weaning weight when forage grazed by the cow herd does not allow calves to attain their genetic potential, however, intensive management is required.

The Institutional Review Board (IRB) and Faculty: Does the IRB Challenge Faculty Professionalism in the Social Sciences?

Institutional Review Boards (IRB) were instituted to protect the rights of research participants and due to past (and at times egregious) practices committed in the name of research. We question whether the IRB is currently overstepping its bounds into the domain of the researcher. We illustrate possible ways in which the IRB subtlety and not so subtlety challenge faculty professionalism and limit faculty research independence, highlighting some instances in which qualitative research topics bump up against boards that mistrust or misunderstand the nature of qualitative research. Using case study vignettes from five universities, our concerns focused on mission creep and potentially legitimating censorship. Areas of mission creep can include institutional reputation, methodological design, and chilling/legal language verses accessible language. In addition we consider multisite studies and when committees focus too much on form rather than content.

Does light attract piglets to the creep area?

Hypothermia, experienced by piglets, has been related to piglet deaths and high and early use of a heated creep area is considered important to prevent hypothermia. The aims of the present study were to investigate how a newly invented radiant heat source, eHeat, would affect piglets’ use of the creep area and whether light in the creep area works as an attractant on piglets. A total of 39 sows, divided between two batches, were randomly distributed to three heat source treatments: (1) standard infrared heat lamp (CONT, n=19), (2) eHeat with light (EL, n=10) and (3) eHeat without light (ENL, n=10). Recordings of piglets’ use of the creep area were made as scan sampling every 10 min for 3 h during two periods, one in daylight (0900 to 1200 h) and one in darkness (2100 to 2400 h), on day 1, 2, 3, 7, 14 and 21 postpartum. On the same days, piglets were weighted. Results showed an interaction between treatment and observation period (P<0.05) with a lower use of the creep area during darkness compared with daylight for CONT and EL litters, but not for ENL litters. Piglets average daily weight gain was not affected by treatment, but was positively correlated with piglets’ birth weight and was lower in batch 1 compared with batch 2. Seen from the present results, neither eHeat nor light worked as an attractant on piglets; in contrast, piglets preferred to sleep in the dark and it would therefore be recommended to turn off the light in the creep area during darkness. Heating up the creep area without light can be accomplished by using a radiant heat source such as eHeat in contrast to the normally used light-emitting infrared heat lamp.