Evaluation of inverse integral transforms for undergraduate physics students

We provide a simple approach for the evaluation of inverse integral transforms that does not require any knowledge of complex analysis. The central idea behind the method is to reduce the inverse transform to the solution of an ordinary differential equation. We illustrate the utility of the approach by providing examples of the evaluation of transforms, without the use of tables. We also demonstrate how the method may be used to obtain a general representation of a function in the form of a series involving the Dirac-delta distribution and its derivatives, which has applications in quantum mechanics, semi-classical, and nuclear physics.Comment: 21 Pages, No Figure

Investigation of efficient methods for the determination of Strassen-type algorithms for fast matrix multiplication

1 online resource (54 p.) : ill.Includes abstract and appendix.Includes bibliographical references (p. 32-33).Fast matrix multiplication algorithms such as the Strassen algorithm allow for the multiplication of matrices with fewer multiplications than would normally be needed, thus making the calculations more efficient. We introduce an efficient and highly parallelizable method for searching for Strassen-type fast matrix multiplication algorithms for multiplying two 2 x 2 matrices, and discuss its application in searching for algorithms that perform fast matrix multiplies for the 3 x 3 case. Searching for these algorithms is difficult, because the search space of possible algorithms is extremely large. The method introduced in this thesis, for the 2 x 2 case, makes use of a grid representation for the matrix multiplication algorithms, making it easier to view patterns in the algorithms and prune the search space effectively. The method is implemented in the Scilab language and is able to find all Strassen-type fast matrix multiplication algorithms in about 90 minutes of computing time on an Intel Core i7 6700k CPU. Based on the insight we gain from the 2 x 2 case, we provide suggestions for an efficient search method for the 3 x 3 case

Providing Grid Services With Heat Pumps: A Review

Abstract The integration of variable and intermittent renewable energy generation into the power system is a grand challenge to our efforts to achieve a sustainable future. Flexible demand is one solution to this challenge, where the demand can be controlled to follow energy supply, rather than the conventional way of controlling energy supply to follow demand. Recent research has shown that electric building climate control systems like heat pumps can provide this demand flexibility by effectively storing energy as heat in the thermal mass of the building. While some forms of heat pump demand flexibility have been implemented in the form of peak pricing and utility demand response programs, controlling heat pumps to provide ancillary services like frequency regulation, load following, and reserve have yet to be widely implemented. In this paper, we review the recent advances and remaining challenges in controlling heat pumps to provide these grid services. This analysis includes heat pump and building modeling, control methods both for isolated heat pumps and heat pumps in aggregate, and the potential implications that this concept has on the power system

Evaluation of growth performance, carcass characteristics, and methane and CO\u3csub\u3e2\u3c/sub\u3e emissions of growing and finishing cattle raised in extensive or partial-intensive cow-calf production systems

An experiment was conducted over 2 yr to measure performance and greenhouse gas (GHG) emissions of weaned calves from two cow-calf production systems. Crossbred steers and heifers (n = 270, initial body weight (BW) = 207 kg, SD = 35) were used in a randomized complete block design, with treatments applied to the cow-calf system. Treatments were: 1) a traditional system consisting of April to June calving with smooth bromegrass pasture and grazed corn residue as forage resources (TRAD); 2) an alternative system consisting of July to September calving utilizing partial-drylot feeding, summer-planted oats, and corn residue grazing (ALT). Calves from both production systems were weaned at the same age and grown (diet NEg = 1.05 Mcal kg–1) for approximately 117 d. The calves then transitioned to a high-grain finishing diet (year 1: NEg = 1.32 Mcal kg–1; year 2: NEg = 1.39 Mcal kg–1) and fed to a targeted 1.52 cm backfat. Growth performance in the grower phase resulted in greater (P \u3c 0.01) average daily gain (1.39 vs. 1.22 ± 0.02 kg), greater gain:feed (P \u3c 0.01; 0.157 vs. 0.137 ± 0.003) for ALT calves compared to TRAD calves, However, a lower initial BW (P \u3c 0.01; 185 vs. 229 ± 4.9 kg) resulted in a lower ending BW (P \u3c 0.01; 347 vs. 371 ± 2.9 kg) for ALT calves compared to TRAD calves in spite of improved growth performance. In the finisher phase, ALT calves gained less (1.52 vs. 1.81 ± 0.218 kg; P = 0.02), were less efficient (0.139 vs. 173 ± 0.0151; P = 0.01) but exhibited similar hot carcass weights (HCW) (388 vs. 381 ± 3.8 kg; P = 0.14) compared to TRAD calves. Each pen of calves was put into a large pen-scale chamber that continuously measured carbon dioxide (CO2 ) and methane (CH4 ) for 5 d during the grower and finisher phases. The average CH4 and CO2 production per unit of feed intake was used to calculate total GHG emissions over the entire grower and finisher phase. Overall, there were no differences (P ≥ 0.17) between treatments for CH4 per day and per kilogram dry matter intake (DMI). However, ALT calves tended to produce less (P ≤ 0.10) CO2 per day and per kilogram DMI than TRAD calves. Overall, methane emissions were greater in ALT calves (110.7 vs. 92.2 ± 8.3 g CH4 kg–1 HCW; P = 0.04) than TRAD calves. The ALT calves required 27 additional days on feed to market, which resulted in more total CH4 per animal across the entire feeding period (P = 0.02) than TRAD calves. Production systems that reduce days to market to achieve similar HCW may reduce GHG emissions

Impact of Corn Silage Inclusion on Finishing Cattle Performance

Cattle fed high grain diets with little to no roughage are typically at greater risk for acidosis and reduced dry matter intake and average daily gain. An individual feeding study was conducted to compare different inclusions of corn silage used as a roughage source on finishing performance and liver abscess rate. Treatments consisted of 3 inclusions of corn silage at 0, 7.5 and 15% of the diet DM and a control treatment with 7.5% alfalfa. There were no differences for live animal performance or carcass characteristics. There were also no differences in liver abscess incidence. Feeding corn silage at 15% gave similar performance responses compared to 7.5% alfalfa. These data suggest that roughage is not required in a finishing diet when feeding individual animals

Evaluation of Protein from Distillers Grains in Finishing Diets on Nutrient Digestibility

A metabolism trial was conducted to evaluate protein from modified distillers grains plus solubles (MDGS) in finishing diets on nutrient digestibility and ruminal fermentation characteristics. Isolated protein from corn was not different than MDGS for dry matter, organic matter, or neutral detergent fiber digestibility. However, steers fed MDGS tended to have lower total tract organic matter digestibility compared to corn and protein from corn. Protein had greater total tract organic matter and starch digestibility than MDGS. Protein from corn did not contribute towards the lower digestibility of MDGS. Protein is more easily digestible than the other components in distillers grains plus solubles

Evaluation of Protein from Distillers Grains in Finishing Diets on Nutrient Digestibility

A metabolism trial was conducted to evaluate protein from modified distillers grains plus solubles (MDGS) in finishing diets on nutrient digestibility and ruminal fermentation characteristics. Isolated protein from corn was not different than MDGS for dry matter, organic matter, or neutral detergent fiber digestibility. However, steers fed MDGS tended to have lower total tract organic matter digestibility compared to corn and protein from corn. Protein had greater total tract organic matter and starch digestibility than MDGS. Protein from corn did not contribute towards the lower digestibility of MDGS. Protein is more easily digestible than the other components in distillers grains plus solubles

Blackcurrants Reduce the Risk of Postmenopausal Osteoporosis: A Pilot Double-Blind, Randomized, Placebo-Controlled Clinical Trial.

Beneficial effects of blackcurrant supplementation on bone metabolism in mice has recently been demonstrated, but no studies are available in humans. The current study aimed to examine the dose-dependent effects of blackcurrant in preventing bone loss and the underlying mechanisms of action in adult women. Forty peri- and early postmenopausal women were randomly assigned into one of three treatment groups for 6 months: (1) a placebo (control group, n = 13); (2) 392 mg/day of blackcurrant powder (low blackcurrant, BC, group, n = 16); and (3) 784 mg/day of blackcurrant powder (high BC group, n = 11). The significance of differences in outcome variables was tested by repeated-measures ANOVA with treatment and time as between- and within-subject factors, respectively. Overall, blackcurrant supplementation decreased the loss of whole-body bone mineral density (BMD) compared to the control group (p \u3c 0.05), though the improvement of whole-body BMD remained significant only in the high BC group (p \u3c 0.05). Blackcurrant supplementation also led to a significant increase in serum amino-terminal propeptide of type 1 procollagen (P1NP), a marker of bone formation (p \u3c 0.05). These findings suggest that daily consumption of 784 mg of blackcurrant powder for six months mitigates the risk of postmenopausal bone loss, potentially through enhancing bone formation. Further studies of larger samples with various skeletal conditions are warranted to confirm these findings