Marginal detonation in ternary systems of hydrocarbons, oxygen and nitrogen

Imperial Users onl

Designing neural networks for the prediction of the drilling parameters for Kuwait oil and gas fields

In this study a new methodology was developed to predict the drilling parameters using the Artificial Neural Network. Three models were developed to predict bit type, rate of penetration (ROP), and cost-per-foot (cost/ft), respectively.;The prediction of bit type and other drilling parameters from the current available data is an important criterion in selecting the most cost efficient bit. History of bit runs plays an important factor in bit selection and bit design. Based on field data, the selection of bit type can be accomplished by the use of a neural network as an alternative bit selection method.;Three drilling parameters were modeled with data from different fields located in Kuwait. Results show that the drilling parameters of the new well can be predicted with the neural network models developed from the previous wells, a cost efficient alternative

A Case for Redundant Arrays of Hybrid Disks (RAHD)

Hybrid Hard Disk Drive was originally concepted by Samsung, which incorporates a Flash memory in a magnetic disk. The combined ultra-high-density benefits of magnetic storage and the low-power and fast read access of NAND technology inspires us to construct Redundant Arrays of Hybrid Disks (RAHD) to offer a possible alternative to today’s Redundant Arrays of Independent Disks (RAIDs) and/or Massive Arrays of Idle Disks (MAIDs). We first design an internal management system (including Energy-Efficient Control) for hybrid disks. Three traces collected from real systems as well as a synthetic trace are then used to evaluate the RAHD arrays. The trace-driven experimental results show: in the high speed mode, a RAHD outplays the purely-magnetic-disk-based RAIDs by a factor of 2.4–4; in the energy-efficient mode, a RAHD4/5 can save up to 89% of energy at little performance degradationPeer reviewe

SAT based Enforcement of Domotic Effects in Smart Environments

The emergence of economically viable and efficient sensor technology provided impetus to the development of smart devices (or appliances). Modern smart environments are equipped with a multitude of smart devices and sensors, aimed at delivering intelligent services to the users of smart environments. The presence of these diverse smart devices has raised a major problem of managing environments. A rising solution to the problem is the modeling of user goals and intentions, and then interacting with the environments using user defined goals. `Domotic Effects' is a user goal modeling framework, which provides Ambient Intelligence (AmI) designers and integrators with an abstract layer that enables the definition of generic goals in a smart environment, in a declarative way, which can be used to design and develop intelligent applications. The high-level nature of domotic effects also allows the residents to program their personal space as they see fit: they can define different achievement criteria for a particular generic goal, e.g., by defining a combination of devices having some particular states, by using domain-specific custom operators. This paper describes an approach for the automatic enforcement of domotic effects in case of the Boolean application domain, suitable for intelligent monitoring and control in domotic environments. Effect enforcement is the ability to determine device configurations that can achieve a set of generic goals (domotic effects). The paper also presents an architecture to implement the enforcement of Boolean domotic effects, and results obtained from carried out experiments prove the feasibility of the proposed approach and highlight the responsiveness of the implemented effect enforcement architectur

Diagnosing students' difficulties in learning mathematics

This study considers the results of a diagnostic test of student difficulty and contrasts the difference in performance between the lower attaining quartile and the higher quartile. It illustrates a difference in qualitative thinking between those who succeed and those who fail in mathematics, illustrating a theory that those who fail are performing a more difficult type of mathematics (coordinating procedures) than those who succeed (manipulating concepts). Students who have to coordinate or reverse processes in time will encounter far greater difficulty than those who can manipulate symbols in a flexible way. The consequences of such a dichotomy and implications for remediation are then considered

Utjecaj glutaraldehida na svojstva želatinskih filmova

In this work gelatin film was prepared from cow\u27s bone. In order to increase mechanical stability of the prepared transparent film as well as decrease its swelling, glutaraldehyde (GTA) was used. Different mass fractions of GTA were utilized. It was observed that at w = 0.18 % of GTA the load at break of the film is δ= 53.7 N and the solubility decreased. The solubility of the film was measured as a dependant parameter of the swelling behavior. In this case it was decreased from 389 % to 156 % at 5 min for gelatin films without GTA and with 0.18 % GTA, respectively. FTIR spectroscopy results showed a peak for crosslinked gelatin at ΰ = 1650 cm-1. It means the crosslinking between gelatin and GTA has taken place. SEM micrographs confirm the porosity has decreased by increasing the GTA fraction, which is an indication of higher strength.U ovom je radu pripremljen želatinski film od kravlje kosti. Da bi se povećala mehanička stabilnost pripremljenog transparentnog filma kao i smanjilo njegovo bubrenje, upotrijebljen je glutaraldehid (GTA). Upotrijebljeni su različiti maseni udjeli mase GTA. Uočeno je da kod 0,18 % GTA prekidna sila filma iznosi 53,7 N i da se povećala topljivost. Topljivost filma izmjerena je kao parametar ovisan o ponašanju pri bubrenju. U ovom slučaju smanjio se s 389 % na 156 % kod 5 minuta za želatinske filmove bez GTA odn. s 0,18 % GTA. Rezultati spektroskopije FTIR pokazali su maksimum za umreženu želatinu kod 1650 cm-1. To znači da je došlo do umrežavanja između želatine i GTA. Mikroskopske slike SEM potvrđuju da se poroznost smanjila povećanjem dijela GTA, što je pokazatelj veće čvrstoće