Biogeochemical Changes During Bio-cementation Mediated by Stimulated and Augmented Ureolytic Microorganisms.

Microbially Induced Calcite Precipitation (MICP) is a bio-mediated cementation process that can improve the engineering properties of granular soils through the precipitation of calcite. The process is made possible by soil microorganisms containing urease enzymes, which hydrolyze urea and enable carbonate ions to become available for precipitation. While most researchers have injected non-native ureolytic bacteria to complete bio-cementation, enrichment of native ureolytic microorganisms may enable reductions in process treatment costs and environmental impacts. In this study, a large-scale bio-cementation experiment involving two 1.7-meter diameter tanks and a complementary soil column experiment were performed to investigate biogeochemical differences between bio-cementation mediated by either native or augmented (Sporosarcina pasteurii) ureolytic microorganisms. Although post-treatment distributions of calcite and engineering properties were similar between approaches, the results of this study suggest that significant differences in ureolysis rates and related precipitation rates between native and augmented microbial communities may influence the temporal progression and spatial distribution of bio-cementation, solution biogeochemical changes, and precipitate microstructure. The role of urea hydrolysis in enabling calcite precipitation through sustained super-saturation following treatment injections is explored

Micro-scale visualization of Microbial-Induced Calcium Carbonate Precipitation (MICP) processes

Microbial-Induced Calcium Carbonate (CaCO₃ ) Precipitation (MICP) has been explored for its potential engineering applications such as soil stabilization, but our understanding of the fundamental MICP processes at the microscale is limited. In this study, real-time in situ micro-scale experiments were conducted using glass slides and microfluidic chips (synthetic porous media which simulate soil matrices to model the conditions similar to actual MICP treatments) to visualize the CaCO₃ precipitation process. The results of this study show that irregularly-shaped CaCO₃ precipitates initially emerged on bacterial aggregates and subsequently dissolved with time as regularly-shaped CaCO₃ crystals started growing; less stable and smaller CaCO₃ crystals may dissolve at the expense of growth of more stable and larger CaCO₃ crystals. The time-dependent phase transformation of CaCO₃ precipitates makes the size of the crystals formed during MICP highly dependent on the time interval between cementation solution injections during a staged injection procedure. When the injection interval was 3-5 hours, a larger number of crystals (200-1000 per 10⁶ μm³) with smaller sizes (5-10 μm) was produced. When the injection interval was longer (23-25 hours), the crystals were larger (10-80 μm) and fewer in number (5-20 per 10⁶ μm³). The direct observation of MICP processes in this study improves the understanding of MICP fundamentals and the effect of MICP processes on the properties of CaCO₃ crystals formed after MICP treatment. These observations will therefore be useful for designing future MICP treatment protocols which improve the properties and sustainability of MICP-treated samples

Effects of Sample Disturbance and Consolidation Procedures on Cyclic Strengths of Intermediate Soils

Sampling and testing of soils to measure engineering properties, such as monotonic and cyclic undrained shear strengths, requires an understanding of the potential effects of sampling disturbance and the selection of appropriate laboratory testing procedures. For clays, past research has provided insights on how sampling methods and laboratory testing procedures can be used in practice to assess and minimize sample disturbance effects. For sands, past research has shown that conventional tube sampling techniques cause excessive disturbance to the soil fabric, such that subsequent measurement of monotonic or cyclic strengths can be greatly in error and misleading. For intermediate soils, the effects of disturbance and consolidation procedures on monotonic and cyclic strengths are not well understood. In the present study, a test protocol was developed to assess the effects that disturbance during sample extrusion, trimming, and mounting have on subsequent measurements of compressibility, monotonic undrained strength, and cyclic undrained strength. Detailed laboratory tests were performed on tube samples from deposits of low-plasticity silty clay, for which conventional sampling and testing were expected to work reasonably well, and low-plasticity clayey sand, for which the effects of sample disturbance were of primary concern. Test results using this protocol for these two soils are presented and discussed

Evaluation of different oil sources for nursery pigs

A total of 210 pigs (PIC 327 × 1050, initially 28.9 lb BW) were used in a 21-d trial to evaluate the effects of increasing oil sources on nursery pig growth performance. The 2 oil sources included a commercial source of soybean oil and a proprietary source of corn oil originating from the ethanol industry (Corn Oil ONE, Feed Energy Co., Pleasant Hill, IA). The 5 experimental diets included: a control diet without added oil, diets with 2.5 or 5% added soybean oil, or diets with 2.5 and 5% added corn oil. Diets were formulated with an identical standardized ileal digestible lysine:calorie ratio and were fed in meal form. There were 6 pens per treatment with 7 pigs per pen. Overall, from d 0 to 21, no oil source × level interactions were observed. Increasing corn oil or soybean oil had no effect on ADG or final BW. Increasing corn oil or soybean oil decreased (linear, P \u3c 0.05) ADFI, which resulted in improved (linear, P \u3c 0.01) F/G. Caloric efficiency was not affected by oil source or level. Feed cost per pig tended to decrease (linear, P = 0.066) for pigs fed increasing levels of soy oil. Cost per pound of gain decreased for both Corn Oil ONE (linear, P = 0.032) and soybean oil (linear, P = 0.008) as oil level increased. Value of the weight gain and income over feed cost was similar for pigs fed diets with Corn Oil ONE and soybean oil (P = 0.833). This study shows the benefits of adding a dietary oil source in late-phase nursery diets to achieve improved feed efficiency. Corn Oil ONE is a suitable alternative for soybean oil, and cost and availability should dictate which source is used.; Swine Day, Manhattan, KS, November 20, 201

Effects of dietary zinc oxide and chlortetracycline on nursery pig growth performance

Swine Industry Day, 2014 is known as Swine Day, 2014A total of 240 weaned pigs (PIC 1050; initially 13.4 lb) were used in a 47-d study to compare the effects of added Zn from zinc oxide (ZnO), alone or in combination with a low or high dose of chlortetracycline (CTC), on nursery pig performance. Pigs were allotted to pens at weaning (d 0) and fed a common starter diet with no antimicrobial for 5 d before the start of the experiment. On d 5, pens of 5 pigs were allotted to 1 of 6 dietary treatments in a randomized complete block design with 8 replications per treatment. Dietary treatments were arranged in a 2 × 3 factorial with main effects of added ZnO (0 vs. 2,500 ppm of Zn) and CTC (0, 50, or 400 g/ton). Pigs were fed experimental diets from d 5 to 26 after weaning followed by a common corn-soybean meal–based diet without antimicrobial from d 26 to 47. Pigs on the 50 g/ton treatment received CTC continuously from d 5 to 26; however, to comply with FDA guidelines, CTC was removed on d 15 from the diets of pigs fed 400 g/ton CTC, then added again from d 16 to 26. All diets contained 110 ppm of Zn from ZnO in the trace mineral premix. No ZnO × CTC interactions were observed. Pigs fed added ZnO had increased (P = 0.001) ADG, ADFI, and ending BW during the treatment period but increased F/G (P = 0.03) from d 26 to 47 when a common diet was fed. Pigs fed CTC had increased (linear, P < 0.05) ADG, ADFI, and ending BW during the treatment period as well as a tendency (quadratic, P = 0.08) for improved F/G. Overall (d 5 to 47), pigs fed added ZnO had increased (P < 0.05) ADG and ADFI. Overall, pigs fed CTC tended to have increased (linear, P = 0.06) ADG and ADFI, but F/G tended (quadratic, P = 0.07) to decrease then increase as CTC increased. In summary, when ZnO or CTC were added to the diets, increased ADG and ADFI were observed, but additional carryover benefits were not evident after these feed additives were removed from the diets. The benefits of added Zn from ZnO and CTC are additive and could be included together in diets to get the maximum benefit in growth performance of weaned pigs

Comparative effects of dietary copper, zinc, essential oils, and chlortetracycline on nursery pig growth performance

Swine Industry Day, 2014 is known as Swine Day, 2014A total of 350 weaned pigs (PIC 1050; initially 13.3 lb) were used in a 47-d study to compare the effects of feeding antibiotic alternatives (copper, zinc, and essential oils), alone or in combination, on nursery pig performance. Pigs were allotted to pens at weaning (d 0) and fed a common starter diet with no antimicrobial for 5 d before the start of the experiment. On d 5, pens of 5 pigs were allotted to 1 of 10 dietary treatments in a randomized complete block design with 7 replications per treatment. Dietary treatments were arranged in a 2 × 2 × 2 + 2 factorial with main effects of added copper sulfate (CuSO4; 0 vs. 125 ppm Cu), added zinc oxide (ZnO; none vs. 3,000 ppm Zn from d 5 to 12 and 2,000 ppm Zn from d 12 to 33), and Regano EX (0 vs. 45 g/ton essential oils blend; Ralco Animal Nutrition, Marshall, MN). The 2 additional treatments were growth-promoting and therapeutic levels of chlortetracycline (CTC at 50 or 400 g/ton). Pigs were fed experimental diets from d 5 to 33 followed by a common corn-soybean meal–based diet without any antimicrobial, essential oils, or pharmacological levels of Cu or Zn from d 33 to 47. To comply with FDA guidelines, CTC was removed on d 19 from the diet of pigs fed 400 g/ton CTC, then added again from d 20 to 33. All diets contained 16.5 ppm Cu and 165 ppm of Zn from the trace mineral premix. Essential oils had no effect on daily gain, but feeding CTC or pharmacological levels of Cu or Zn improved the growth rate of nursery pigs. Carryover effects from any of these dietary treatments on subsequent nursery growth performance were minimal. Although there were no improvements in feed efficiency due to Cu or Zn, the inclusion of an essential oils blend worsened feed and caloric efficiencies

Comparison of soybean oil and different sources of corn oil on nursery pig growth performance

A total of 350 pigs (PIC 1050; initially 26.45 ± 0.09 lb and 45 d of age) were used in a 21-d study to compare the effects of soy oil and 2 sources of corn oil on nursery pig growth performance. The 7 dietary treatments consisted of a corn-soybean meal–based control diet with no added oil or the control diet with 2.5 or 5% soybean oil (NE = 3,422 kcal/lb) or corn oil from 2 different sources (NE = 3,383 kcal/kg for both sources). There were 5 pigs per pen and 10 pens per treatment. Pig weight and feed disappearance were measured on day 0, 7, 14, and 21 of the trial to determine ADG, ADFI, and F/G. Overall (d 0 to 21), increasing corn or soybean oil improved (linear; P \u3c 0.02) ADG, F/G, and final (d-21) BW, but a source × level interaction was observed (P \u3c 0.05) for ADG, F/G, and caloric efficiency (CE; caloric intake/total BW gain). For ADG, increasing soy oil or corn oil source 1 from 2.5 to 5% increased ADG, whereas increasing corn oil source 2 from 2.5 to 5% decreased ADG. Feed efficiency also improved at a greater rate for pigs fed increasing corn oil source 1 compared with the other oil sources. Caloric efficiency was not influenced by soy oil or corn oil source 2 but was improved (linear, P \u3c 0.05) as corn oil source 1 increased in the diet. The improved CE for corn oil source 1 indicated that the energy value of this source was underestimated. In conclusion, soybean or corn oil improved ADG and F/G as expected; however, growth performance varied among the 3 oil sources. This study shows the benefits of adding an oil source in late-phase nursery pig diets to achieve improved ADG, F/G, and CE, but more research is needed to determine the cause of the varied responses between corn oil sources.; Swine Day, Manhattan, KS, November 20, 201

Reusable Instrumented Test Pile Phase 2

65A0481The performance and constructability of pile foundations in coarse granular soils contains significant uncertainty due to challenges in site characterization and uncertainty in pile prediction methods. The Reusable Test Pile idea was conceived as a large diameter instrumented test pile that could be deployed during the site investigation phase of a project where a deep foundation design and or coarse grained soils were expected. Static and dynamic data obtained by the RTP during this phase was envisioned to be useful to designers and contractors for assessing soil properties, pile drivability, and pile performance (capacity, displacement). This report contains four journal papers and a M.S.C.E. thesis that describe the equipment design, data collected, and data processing and interpretation as it applies to evaluating penetration resistance, soil properties, pile driving dynamics, and static pile loading behavior. This includes an initial formulation for static pile capacity estimation based on RTP data and considerations for dynamic pile modeling

Evaluation of different oil sources for nursery pigs

A total of 210 pigs (PIC 327 × 1050, initially 28.9 lb BW) were used in a 21-d trial to evaluate the effects of increasing oil sources on nursery pig growth performance. The 2 oil sources included a commercial source of soybean oil and a proprietary source of corn oil originating from the ethanol industry (Corn Oil ONE, Feed Energy Co., Pleasant Hill, IA). The 5 experimental diets included: a control diet without added oil, diets with 2.5 or 5% added soybean oil, or diets with 2.5 and 5% added corn oil. Diets were formulated with an identical standardized ileal digestible lysine:calorie ratio and were fed in meal form. There were 6 pens per treatment with 7 pigs per pen. Overall, from d 0 to 21, no oil source × level interactions were observed. Increasing corn oil or soybean oil had no effect on ADG or final BW. Increasing corn oil or soybean oil decreased (linear, P \u3c 0.05) ADFI, which resulted in improved (linear, P \u3c 0.01) F/G. Caloric efficiency was not affected by oil source or level. Feed cost per pig tended to decrease (linear, P = 0.066) for pigs fed increasing levels of soy oil. Cost per pound of gain decreased for both Corn Oil ONE (linear, P = 0.032) and soybean oil (linear, P = 0.008) as oil level increased. Value of the weight gain and income over feed cost was similar for pigs fed diets with Corn Oil ONE and soybean oil (P = 0.833). This study shows the benefits of adding a dietary oil source in late-phase nursery diets to achieve improved feed efficiency. Corn Oil ONE is a suitable alternative for soybean oil, and cost and availability should dictate which source is used.; Swine Day, Manhattan, KS, November 20, 201