Microscopic Wear Characteristics of Ceramic Grinding Wheel in Creep Feed Grinding

This paper deals with the microscopic wear characteristics of ceramic (Seeded Gel, SG) grinding wheels used in creep feed grinding. Creep feed grinding experiments with SG grinding wheels were carried out compared to rose-pink alumina (RA) grinding wheels. To clear the wear characteristics of the wheel working surface in creep feed grinding, changes in the shapes of grain cutting edges were observed by a field emission-scanning electron microscope (FE-SEM). This is a self-sharpening phenomenon based on micro fractures generated on the top of SG grain cutting edges. On the other hand, large fracture and attritious wear effected RA grain cutting edges. In addition, the features of any grain cutting edges were evaluated using attritious wear flat percentage. Changes in attritious wear flat percentage of SG grits maintained constant value and were stable. From these results, the influence of wear mode of the grinding wheel on grinding characteristics parameter, such as grinding force and workpiece surface roughness, is understood.

Special Issue on High Performance Abrasive Technologies

Demand for the high-precision and high-efficiency machining of hard ceramics, such as silicon carbide for semiconductors and hardened steel for molding dies, has significantly increased for optical and medical devices as well as for powered devices in automobiles. Certain types of hard metals can be machined by deterministic precision-cutting processes. However, hard and brittle ceramics, hardened steel for molds, and semiconductor materials have to be machined using precision abrasive technologies, such as grinding, polishing, and ultrasonic vibration technologies that use diamond super abrasives. The machining of high-precision components and their molds/dies using abrasive processes is very difficult due to their complex and nondeterministic natures as well as their complex textured surfaces. Furthermore, the development of new cutting-edge tools or machining methods and the active use of physicochemical phenomena are key to the development of high-precision and high-efficiency machining. This special issue features 11 research papers on the most recent advances in precision abrasive technologies. These papers cover the following topics: - Characteristics of abrasive grains in creep-feed grinding - Quantitative evaluation of the surface profiles of grinding wheels - ELID grinding using elastic wheels - Nano-topographies of ground surfaces - Novel grinding wheels - Grinding characteristics of turbine blade materials - Polishing mechanisms - Polishing technologies using magnetic fluid slurries - Application of ultrasonic vibration machining - Turning and rotary cutting technologies This issue is expected to help its readers to understand recent developments in abrasive technologies and to lead to further research. We deeply appreciate the careful work of all the authors, and we thank the reviewers for their incisive efforts.

The effect of creep feed composition and form on pre- and post-weaning growth performance of pigs and the utilization of low-complexity nursery diets

Fifty-six litters from first-parity sows standardized to 12 piglets were used to determine the effects of creep feed composition and form on pre- and post-weaning pig growth performance and the utilization of low-complexity nursery diets. At five days of age, litters (initial BW 2.31±0.61 kg) were assigned to one of four creep feeding regimens (n=14): [1] pelleted commercial creep feed (COM), [2] liquid milk replacer (LMR), [3] pelleted milk replacer (PMR), or [4] no creep feed (NO); creep feeds contained 1.0 % brilliant blue as a fecal marker. Individual piglet BW and fecal swabs were collected every 3±1 days during the creep-feeding period. The latter was to identify piglets that regularly consumed creep feed via the visual appearance of blue dye in the feces. At weaning (21±2 days of age), six pigs per litter with median BW that consumed creep feed were placed on either a HIGH- (contained highly digestible animal proteins) or LOW- (contained corn and soybean meal as the main protein sources) complexity nursery diet (n=7) in a three-phase feeding program over 39 days. On day 8, two pigs per pen were sacrificed to collect organ weights and digesta. The LMR disappeared at the greatest rate (average 37.7 g/pig/d; DM-basis) versus COM and PMR (10.6 and 10.3 ± 1.5 g/pig/d, respectively; P < 0.001). Litters that received LMR had the greatest proportion of pigs with blue fecal swabs throughout the creep feeding period (85.0 vs. 54.9 and 63.0 ± 0.4% for COM and PMR, respectively; P < 0.05) and LMR piglets had greater BW at weaning versus all other treatments (6.32 vs. 6.02, 5.92, and 5.67 ± 0.14 kg, for LMR, COM, NO, and PMR, respectively; P < 0.001). Overall, pigs given LOW (versus HIGH) diets in the nursery period had reduced ADG (25.1 vs. 27.7 ± 0.4 g/kg BW; P < 0.001), G:F (0.75 vs. 0.81 ± 0.02; P < 0.001), and exit BW (21.2 vs. 24.4 ± 0.6 kg; P < 0.001); no carryover effects of creep feeding program were observed. Creep feed regimen had limited effects on nutrient digestibility of nursery diets but the apparent ileal digestibility of organic matter tended to be less at 28 days of age for pigs that received the LOW nursery diet (64.2 vs. 68.8 ± 2.5%; P = 0.076). Providing supplemental nutrition during the suckling period via LMR improved piglet BW at weaning, which did not correspond to improved post-weaning growth performance, regardless of nursery diet complexity.

The Effect of Feeding Liquid or Dry Creep Feed on Growth Performance, Feed Disappearance, Enzyme Activity and Number of Eaters in Suckling Piglets

The aim of this study was to investigate the effect of two dietary treatments (liquid creep feed (LCF) and dry creep feed (DCF)) offered during the suckling period on feed disappearance, number of eaters, and intestinal enzymatic development at weaning in an on-farm study with 347 piglets. Piglets were allocated to either the DCF or LCF treatment from day 10 to day 24 postpartum for 9 h a day. Red ferric oxide (1%) was added to the diet to categorize piglets into eating categories (good eaters, moderate eaters, or non-eaters) via faecal swabs. At weaning, 40 piglets were sampled for intestinal enzymatic development. The LCF treatment increased the dry matter disappearance from day 10–18 (p < 0.001). The percentage of good eaters, moderate eaters and non-eaters did not differ between treatments (p > 0.05). The DCF pigs displayed greater average daily gain (ADG) pre-weaning (p = 0.024), and a greater body weight (BW) at day 61 (p < 0.001). The activity of lactase, maltase and sucrase in the proximal part of the small intestine were greatest (p < 0.001) in the DCF pigs.

Design and Development of Submerged Arc Welding Acidic Flux

An acidic flux was intended and developed with the variation of some flux constituents. The basicity index of the flux was kept as 1.84. It was designed to weld the mild steel plates on submerged arc welding machine. A study was done with developed flux on two-level factorial design. Voltage and current were the controlled parameters along with feed rate, nozzle distance and creep feed as uncontrolled parameters selected for experimentation. Eight experiments were performed. Weld bead width and Hardness were the responses measured. Design expert software was used the do the analysis. Finally, it can be determined that travel speed was the most momentous factor for the hardness and weld bead dimensions of the joint.

PSII-10 Growth rates in piglets after the introduction of spot genetics

Growth curve, ADG, and feed efficiency were measured for Spot pigs. Growth curves are essential for livestock producers to keep a record of growth and feed efficiency as benchmarks used for management goals and consistency. Growth and development data exists for breeds such as Yorkshires and Landraces. However, fewer data are available for pure Spot or introduced Spot genetics. Spots, or Spotted Swine, are a breed of pig with ancestry to the original Poland China. Four litters (n=44) from the same sire were tracked for weight, ADG, and feed conversion from farrowing through nursery. All pigs were housed in DVU’s Swine Science Center, an indoor, temperature, and ventilation-controlled facility. Weights were collected daily farrow to wean and then weekly thereafter. Pigs were introduced to a creep feed at approximately 10 days. Pigs were weaned at 21d (i.e., 3wks). The average weaning weights ranged from 5.0 to 8.3 kg, the ADG for each litter ranged from 0.17 to 0.32 kg. A pelleted 21% crude protein nursery ration was fed ad libitum. Pigs were kept in pens by their respective litter and weights were then collected on a weekly basis for a total of 56 days. The average weights ranged from 41 to 47.1 kg and the ADG ranged from 0.62 to 0.68 kg, and the F:G ratio ranged from 1.48 to 2.88. Statistics were compared using an ANOVA and T-test (Table 1). A p-value where P &lt; 0.05 indicated significant differences in means. Pen 3, a smaller litter size, had significantly higher ADG and final weights. These findings can be compared to data for other breeds on a similar ration to determine if Spot genetics improve feed efficiency.

358 Effect of Molasses Type on Pre-weaning Lamb and Ewe Performance

The objective of this study was to investigate the effects of form of molasses on lamb and ewe performance. Creep feeding of lambs is essential to lamb growth, rumen development, and reduction of milk production from dams. Molasses is often added for increased palatability and energy. Crossbred lambs (n = 47; average age = 30 d) and their accompanying dams (n= 35) were assigned to one of two treatments using a completely randomized design with similar distributions of single and twin-born lambs and sexes. Treatment diets were formulated to be isonitrogenous and contained either wet (WMOL) or dry (DMOL) molasses. Dry molasses was added at 10% of the diet DM, whereas, wet molasses was added at 14.3% of the diet DM. Lambs were fed creep rations for 42 d prior to weaning. Creep feed was provided ad libitum and mixed grass hay was offered free-choice. Lamb weights were recorded weekly until weaning (d 42) and ewe BCS was measured at d 0 and d 42 (weaning). Overall lamb ADG was comparable (DMOL = 0.268 kg/hd, WMOL = 0.293 kg/hd; P = 0.30). Lamb weaning weights were similar between DMOL and WMOL (DMOL = 27.9 kg; WMOL = 27.5; P = 0.79). Ewe BCS was similar (P = 0.88) between DMOL and WMOL at 1.4 and 1.4, respectively. Estimated creep intake was calculated based upon total consumption following the end of the project and was found to be similar between treatments (DMOL = 0.54 kg/hd/d; WMOL = 0.59 kg/hd/d). Lamb pre-weaning growth and ewe performance was similar between DMOL and WMOL. Further research is needed to further explore the economic impact and use post-weaning.

In-Feed Supplementation of Resin Acid-Enriched Composition Modulates Gut Microbiota, Improves Growth Performance, and Reduces Post-Weaning Diarrhea and Gut Inflammation in Piglets

The weaning process represents a delicate phase for piglets, and is often characterized by lower feed intake, lower weight gain, diarrhea, and ultimately increased mortality. We aimed to determine the effects of RAC supplementation in diets on improving piglet growth and vitality, reducing post-weaning diarrhea, and enhancing gut health. In a 2 × 2 × 2 factorial experiment, we selected forty sows and their piglets. Piglets were followed until seven weeks of age. There were no significant differences found between RAC treated and control piglets until weaning (p = 0.26). However, three weeks after weaning, RAC treated piglets had higher body weight and average daily growth (ADG) than the control piglets (p = 0.003). In addition, the piglets that received RAC after weaning, irrespective of mother or prior creep feed treatment, had lower post-weaning diarrhea (PWD) and fecal myeloperoxidase (MPO) level than control piglets. Gut microbiota analysis in post-weaning piglets revealed that RAC supplementation significantly increased Lachnospiraceae_unclassified, Blautia, Butyricicoccus, Gemmiger and Holdemanella, and decreased Bacteroidales_unclassified. Overall, RAC supplementation to piglets modulated post-weaning gut microbiota, improved growth performance after weaning, reduced post-weaning diarrhea and reduced fecal myeloperoxidase levels. We therefore consider RAC to be a potential natural feed supplement to prevent enteric infections and improve growth performance in weaning piglets.