A lower bound on HMOLS with equal sized holes

It is known that $N(n)$, the maximum number of mutually orthogonal latin squares of order $n$, satisfies the lower bound $N(n) \ge n^{1/14.8}$ for large $n$. For $h\ge 2$, relatively little is known about the quantity $N(h^n)$, which denotes the maximum number of `HMOLS' or mutually orthogonal latin squares having a common equipartition into $n$ holes of a fixed size $h$. We generalize a difference matrix method that had been used previously for explicit constructions of HMOLS. An estimate of R.M. Wilson on higher cyclotomic numbers guarantees our construction succeeds in suitably large finite fields. Feeding this into a generalized product construction, we are able to establish the lower bound $N(h^n) \ge (\log n)^{1/\delta}$ for any $\delta>2$ and all $n > n_0(h,\delta)$

Development of a Laboratory Experiment to Simulate Upper-Stage Rocket Explosions

This report is a summary of the senior project entitled Development of a Laboratory Experiment to Simulate Upper-Stage Rocket Explosions. The goal of the experiment was to recreate a NASA experiment which used aluminum soft drink cans to approximate the shape of an Ariane third stage rocket. The cans were placed in a vacuum chamber and fired upon with a projectile from a light gas gun. The resulting debris was collected and analyzed allowing several conclusions to be made regarding the behavior or rocket breakups and the formation of space debris. In lieu of a light gas gun, energy drink cans, fitted with a one-way valve from a bicycle inner tube and filled with a hydrogen and oxygen mixture, are detonated with an Estes model rocket motor igniter. The cans were successfully detonated and aluminum debris was formed in a manner consistent with the predictions of the original experiment. This report describes in detail the preliminary experiments and testing leading to the development of the final apparatus and procedure implemented in the Aerospace Engineering Department’s Spacecraft Environment Laboratory

2-perfect m-cycle systems

AbstractThe spectrum for 2-perfect m-cycle systems of Kn has been considered by several authors in the case when m⩽7. In this paper we essentially solve the problem for 2-perfect m-cycle systems of Kn in the case where m is prime and 2m+1 is a prime power. In particular we settle the problem for m = 11 and 13 except for two or one possible exceptions respectively. The problem for m = 9 is also considered

Lactic acid purification of chitin from prawn waste using a horizontal rotating bioreactor

Shellfish waste obtained from seafood processing plants contains chitin, protein and calcium carbonate. Chitin is a versatile biopolymer with many applications. Conventionally, chitin is separated from calcium carbonate and protein by acid and alkali respectively. In this project, a biotechnological approach was applied to recover chitin from scampi (Nephrops norvegicus) waste using lactic acid bacteria (LAB) to produce lactic acid from glucose which lowers the pH of the mixture, thus preserving the waste from spoilage. The acid also dissolves the calcium carbonate and under these conditions native enzymes breakdown the protein (autolysis), thus affording a substantial amount of purification of chitin. LAB were isolated and identified from various shellfish waste fermentations. Studies on their acid-producing ability revealed a few potentially good strains, identified as Lactobacillus paracasei, Lactobacillus plantarum and Pediococcus sp. The strain of Lactobacillus paracasei was used as a starter culture in the fermentation of shellfish waste in a horizontal rotating bioreactor in order to evaluate the feasibility of the process. The design of the bioreactor was such that it enabled separation of solid and liquid end products during fermentation. Several important fermentation parameters were studied including mode of rotation, concentration of glucose, temperature, rotation rates, loading capacity, type and particle size of waste. Partial purification of the scampi waste was achieved using both batch and fed batch operation, but in the latter, improved purification was achieved at the cost of increased glucose consumption and extended fermentation times. Whilst higher temperatures increased the rates of fermentation, higher rotation rates seemed to have the reverse effect. Mincing the waste helped to increase breakdown of protein whilst larger particles tended to undergo rapid spoilage. Analysis of the chitin product enabled this method to be compared with the conventional method. The results obtained showed that this method is capable of saving large volumes of chemicals and besides producing chitin, the protein liquor by-product could also be used as an ingredient in an animal feed which is not possible by the conventional method

CO2 Based Parachute Deployment

This paper describes the design process of a CO2 based parachute deployment system for the Akronauts Rocket Design team, with particular emphasis on the selection of methodologies of deployment as well as design iteration. The objective was to create a fully mechanical system in order to replace the black powder based systems that were used previously by the team. Emphasis was put in creating a system that would function well at higher altitudes while also preventing damage to the parachute during deployment. This system emphasizes robustness under launch conditions

The 3-GDDs of type g3u2g^3u^2

A 3-GDD of type ${g^3u^2}$ exists if and only if $g$ and $u$ have the same parity, $3$ divides $u$ and $u\leq 3g$.Such a 3-GDD of type ${g^3u^2}$ is equivalent to an edge decomposition of $K_{g,g,g,u,u}$ into triangles