PyFrac: A planar 3D hydraulic fracture simulator

Fluid driven fractures propagate in the upper earth crust either naturally or in response to engineered fluid injections. The quantitative prediction of their evolution is critical in order to better understand their dynamics as well as to optimize their creation. We present a Python implementation of an open-source hydraulic fracture propagation simulator based on the implicit level set algorithm originally developed by Peirce & Detournay (2008) -- "An implicit level set method for modeling hydraulically driven fractures". Comp. Meth. Appl. Mech. Engng, (33-40):2858--2885. This algorithm couples a finite discretization of the fracture with the use of the near tip asymptotic solutions of a steadily propagating semi-infinite hydraulic fracture. This allows to resolve the multi-scale processes governing hydraulic fracture growth accurately, even with relatively coarse meshes. We present an overview of the mathematical formulation, the numerical scheme and the details of our implementation. A series of problems including a radial hydraulic fracture verification benchmark, the propagation of a height contained hydraulic fracture, the lateral spreading of a magmatic dyke and the handling of fracture closure are presented to demonstrate the capabilities, accuracy and robustness of the implemented algorithm

Second Order Corrections to QED Coupling at Low Temperature

We calculate the second order corrections to vacuum polarization tensor of photons at low temperatures, i.e; T $\le 10^{10}$ K ($T << m_e$). The thermal contributions to the QED coupling constant are evaluated at temperatures below the electron mass that is $T< m_e$ . Renormalization of QED at these temperatures has explicitly been checked. The electromagnetic properties of such a thermal medium are modified. Parameters like electric permittivity and magnetic permeability of such a medium are no more constant and become functions of temperature.Comment: 8 latex pages and 1 figure (to appear in IJMP

ProAm Sports

ProAm Sports takes fitness one step further by designing a tournament-based program, where members can sign up to participate in matches as individuals or teams in various sports and win actual cash prizes accumulated from a portion of their membership fees. Our project required implementing a database which stores information on players, teams, and games as well as a website that offers the ability for players to sign up, view information on events, pay for membership, and communicate with other players. There are three levels of paid membership, where each offers different benefits including discounts on event registration. After registering for an event, players can see their registration history and see which other members are registered for the same event. Members are able to interact with other players, compete with other teams, test their skills, and possibly win cash prizes. We implemented the website using Joomla and Community Builder so that the backend is menu-based instead of code-based in order to prove convenient for our sponsor. Extra functionality in the backend includes categorizing events by sport and tournament, making events repeat, and adding special discounts based on registration date. Community Builder also allows all members/players to create connections with each other and leave notes on each other’s profiles. Players are also given the capability of recording their achievements on their respective profiles for other players to view and take into consideration when recruiting for teammates.https://scholarscompass.vcu.edu/capstone/1164/thumbnail.jp

Criminal Procedure: Negligent Suppression of Evidence as Ground for New Trial in Federal Criminal Proceedings

Självkompakterande betong (SKB) eller som den också kallas vibreringsfri betong upptäcktes och utvecklades i Japan i slutet av 1980- talet. Anledningen till detta utvecklingsarbete var att betong gjutning väldigt kämpigt och tillgången på erfarna betongarbetare började bli låg. I Sverige använde man självkompakterande betong året 1993 som tekniken hämtades hem av CBI Betonginstitutet. Användning av självkompakterande betong leder till många fördelar som skiljer sig från den vanliga betongen avseende arbetsmiljö t.ex. slipper man vibrering och undviker tungt arbete som i konsekvens minskar antal skador på arbetsplatsen. Utöver detta ger SKB förkortad arbetstid, bättre utförande och möjlighet till arbetskraftbesparing. Sedan 1997 har Sverige ökat användning av SKB i platsgjutning medan andra länder som Danmark har gått fram till ca 30 % av sin platsgjutning. Den låga användningen beror på att självkompakterande betong är väldigt känslig och dyrare eftersom den innehåller mer tillsatsmaterial. Huvuddelen av projektet bestod av att ställa frågor till experter i byggbranschen om självkompakterande betong för att få största möjliga mängd av informationer. Informationer som vi har fått var emellan åtta besök och sex mail. Syftet med examensarbete är att öka kunskap om orsaken till låg utveckling av SKB på platsgjutning och kunskap om arbetsmiljö. Vidare syftar arbetet till att lyfta fram de arbetsmiljömässiga och konstruktiva fördelarna samt sprida information om dessa. Informationerna visar att anledningen till den låga användningen av SKB framför allt är priset.  Men tidigare misslyckanden och varierande betongegenskaper är också en av anledningarna. Genom att öka användning av SKB där man många fördelar bland annat ekonomisk vinst på lång sikt och framför allt bättre arbetsmiljö med tanke på samhället.Self-compacting concrete (SCC) or vibrated concrete was invented and developed in Japan in the late 1980's. Working with concrete is very hard and all of that is because of injuries that come from using of the usual concrete.  In Sweden, they used self-compacting concrete since 1993 when the technology has brought to Sweden from Japan by the Swedish cement and concrete Research institute. Self-compacting concrete has many advantages that are different from the traditional concrete according to the work environment which include avoidance of vibration and heavy work and all these can reduce the number of injuries at workplace. Shortened construction time and possibilities to save manpower are additional benefits. Today, self-compacting concrete is used for about 10 % on site casting in Sweden. Many other countries have gone forward in using of SCC, Denmark uses about 30%. The low use is due to the sensitivity of SCC and expensive because it contains more filler. The main work of the project consists of the interviews with the related persons in the building branch and questions to them about self-compacting concrete to get the maximum amount of information. Information that we have received was between eight visits and six mail. The aim of the thesis is to increase knowledge about the cause of the low development of SCC in place casting and knowledge of the work environment. Furthermore, this work aims to highlight the work environment and constructive advantages and disseminate information about them. The study shows that the reason for the low use of SCC is especially the price. But the previous failures and varying concrete properties are also such of these reasons. Increasing the use of SCC leads to many benefits including economic profit in the long term, and especially from the society side

Gas absorption into liquid films falling over roughened and vibrating surfaces

Imperial Users onl