Assessing academic writing on a pre-sessional EAP course: Designing assessment which supports learning

Pre-sessional EAP courses in the UK fulfil a difficult dual role. Not only are they charged with helping students learn the academic language and literacy skills they will require on their degree courses, but they are also expected to summatively assess those skills in order to decide on the readiness of students to begin English medium degree study. This creates tension between assessment and learning. Students are often extrinsically motivated by the need for a passing grade rather than focussing on the learning gains they make throughout the course. For this reason it is important that the approach to assessment on pre-sessional courses actually supports learning. This paper outlines the approach taken to the assessment of academic writing on the PEAP course at Nottingham Trent University. It describes how the assessment was redesigned to emphasise process over end product and to maximise early and sustained student engagement. This was achieved by careful scaffolding of the writing process, the strategic use of summative elements of the assessment, and an emphasis on formative feedback, reflection, and understanding of the assessment criteria. The paper considers how this approach to assessment is supporting student learning but also points out some ongoing concerns

Design of Photonic Crystal Klystrons

2D Pho­ton­ic crys­tals (PC) with de­fects can act as stand­ing-wave res­onators, which offer ben­e­fit of high mode se­lec­tiv­i­ty for build­ing novel RF sources. We in­tro­duce our work on de­sign­ing two-cav­i­ty sin­gle-beam and mul­ti-beam klystrons using tri­an­gu­lar lat­tice metal­lic PCs. We pre­sent the cold test re­sults of the stub-cou­pled sin­gle-beam struc­ture, which show that at res­o­nance a very low re­flec­tion can be ob­tained, and the waves are well con­fined. We also pre­sent bead-pull mea­sure­ment re­sults of field strengths in the de­fect, using mod­i­fied per­tur­ba­tion equa­tion for small unit di­elec­tric cylin­der, which are in very good agree­ment to nu­mer­i­cal re­sults. A 6-beam klystron cav­i­ty is de­signed as a 6-cou­pled-de­fect struc­ture with a cen­tral stub, which only cou­ples to the in-phase mode at the low­est fre­quen­cy. Fi­nal­ly, we pre­sent a fea­si­bil­i­ty dis­cus­sion of using this mul­ti-de­fect PC struc­ture to con­struct an in­te­grat­ed klystron-ac­cel­er­a­tor cav­i­ty, along with nu­mer­i­cal re­sults show­ing a peak ac­cel­er­a­tion field of 22MV/m can be achieved

Dispersion Engineering and Disorder in Photonic Crystals for Accelerator Applications

The possibility of achieving higher accelerating gradients at higher frequencies with the reduction of the effect of HOMs, compared to conventional accelerating structures, is increasing interest in the possible use of Photonic Crystals (PC) for accelerator applications. In this paper we analyze how the properties of the lattice of a PC resonator can be engineered to give a specific band structure, and how by tailoring the properties of the lattice specific EM modes can either be confined or moved into the propagation band of the PC. We further go on to discuss the role of disorder in achieving mode confinement and how this can be used to optimize both the Q and the accelerating gradient of a PC based accelerating structure. We also examine the use of high disorder to give rise to Anderson Localization, which gives rise to exponential localization of an EM mode. Discussing the difference between the extended Bloch wave, which extends over the entire PC, and the Anderson localized mode

Giant thermoemf in multiterminal superconductor/normal metal mesoscopic structures

We considered a mesoscopic superconductor/normal metal (S/N) structure in which the N reservoirs are maintained at different temperatures. It is shown that in the absence of current between the N reservoirs a voltage difference $V_{T}$ arises between the superconducting and normal conductors. The voltage $V_{T}$ oscillates with increasing phase difference $\phi$ between the superconductors, and its magnitude does not depend on the small parameter $(T/\epsilon_{F}).$Comment: Resubmited, some changes to Text and Figure

Compact Accelerator Based Neutron Source for Technetium-99M Production

The radioisotope Technetium-99m (99m Tc) is used in 85% of all nuclear medicine procedures. 99mTc is produced from its precursor Molybdenum-99 (99 Mo), whose production is nearly all from one of only five ageing research reactors. Recently a number of accelerator-based methods have been proposed to fill this gap and to diversify this supply chain. In this paper we present a compact (4 m) 10 mA, 3.5 MeV accelerator design, to generate 99Mo via low-energy neutron bombardment of 98Mo. We consider a Li(p,n) target for neutron production, and propose the use of a novel moderator to optimally shift the target output neutron spectrum into the epithermal region of the 98Mo. This paper specifically focuses on numerical studies for an optimised target design capable of handling the thermal load

Effect of Thermal and Mechanical Deformation of Metamaterial FDM Components

At Lancaster University, research is currently investigating the use of rapid manufacturing (RM) to realise metamaterials, although key to the success of this project is the development of an understanding of how coated RM parts deform under thermal and mechanical stress. The research in this paper presents a comparison of the thermal and mechanical deformation behaviour of RM coated metamaterials components from a numerical context. The research uses the design of a simple metamaterial unit cell as a test model for both the experimental and finite element method (FEM). The investigation of deformation behaviour of sample Fused Deposition Modelling (FDM) parts manufactured in different orientations and simulated using commercial FEM code means that the FEM analysis can be utilized for design verification of FDM parts. This research contributes to further research into the development of RM metamaterials, specifically design analysis and verification tools for RM materials

3D Simulation of the Effects of Surface Defects on Field Emitted Electrons

The ev­er-grow­ing de­mand for high­er beam en­er­gies has dra­mat­i­cal­ly in­creased the risk of RF break­down, lim­it­ing the max­i­mum achiev­able ac­cel­er­at­ing gra­di­ent. Field emis­sion is the most fre­quent­ly en­coun­tered RF break­down where it oc­curs at re­gions of lo­cal­ly en­hanced elec­tric field. Elec­trons ac­cel­er­at­ed across the cav­i­ty as they tun­nel through the sur­face in the pres­ence of mi­cro­scop­ic de­fects. Upon Im­pact, most of the ki­net­ic en­er­gy is con­vert­ed into heat and stress. This can in­flict ir­re­versible dam­age to the sur­face, cre­at­ing ad­di­tion­al field emis­sion sites. This work aims to in­ves­ti­gate, through sim­u­la­tion, the physics in­volved dur­ing both emis­sion and im­pact of elec­trons. A newly de­vel­oped 3D field model of an 805 MHz cav­i­ty is gen­er­at­ed by COM­SOL Mul­ti­physics. Elec­tron track­ing is per­formed using a Mat­lab based code, cal­cu­lat­ing the rel­e­vant pa­ram­e­ters need­ed by em­ploy­ing fourth Order Runge Kutta in­te­gra­tion. By study­ing such be­haviours in 3D, it is pos­si­ble to iden­ti­fy how the cav­i­ty sur­face can alter the local RF field and lead to break­down and sub­se­quent dam­ages. The ul­ti­mate aim is to in­tro­duce new sur­face stan­dards to en­sure bet­ter cav­i­ty per­for­mance