Two-point sum-rules in three-dimensional Yang-Mills theory

We compute the stress-tensor two-point function in three-dimensional Yang-Mills theory to three-loops in perturbation theory. Using its calculable shape at high momenta, we test the notion that its Borel transform is saturated at low energies by the lowest glueball state(s). This assumption provides relatively stable estimates for the mass of the lightest glueball that we compare with lattice simulations. We also provide estimates for the coupling of the lightest glueball to the stress tensor. Along the way, we comment on the extent that such estimates are non-rigorous. Lastly, we discuss the possibility of applying the sum-rule analysis to two-point functions of higher-spin operators and obtain a crude approximation for the glueball couplings to these operators.Comment: 31 + 11 pages, 13 figure

Productivity optimization of manufacturing system using computer simulation, design of experiment and response surface methodology

Productivity plays a significant role for most companies in order to measure the efficiency. In reality there is an essential need to evaluate the different factors which increasing productivity and achieving the high level of quality, a high production rate and machine utilization. Therefore, in the manufacturing industry, managers and engineers are seeking to find methods in order to eliminate the common problems in manufacturing systems such as bottlenecks and waiting times. This is because that all of these kinds of problems impose extra cost to the companies. In addition, manufacturing companies are striving to sustain their competitiveness by improving productivity, efficiency and quality of manufacturing industry for instance high throughput and high resource utilization. So it can be acquired by finding ways to deal with various industrial problems which have affected the productivity of manufacturing systems such as high lead time and work-in-progress (WIP) and etc. This thesis concentrates on the application of design of experiment (DOE) and computer simulation to recognize and to weight the significance of different factors in the production line as well as to achieve the optimum productivity. Arena 13.9 software was selected as the simulation software. A case study of color industry was chosen to implement and evaluate the result of applying DOE and response surface methodology (RSM) by using Minitab 16 and Expert-Design 6.5. Data required for developing the simulation model were gathered from the factory documents and stop-watch method. The results reveal that applying computer simulation and design of experiment in the manufacturing systems is very useful and helpful where the weakness of the system will be found after doing the experimentation. Based on the main objectives of this thesis the effect of the factors which have the most significant influence on the productivity was assessed and determined. Finally the best factor setting which result in the maximum productivity was determined

Experimental Investigation of Metal Powder Compaction without Using Lubricant

The main objective of this work was to design a novel device for compaction of metal powders so that the green parts could be ejected with applying a negligible force and without the need for any lubricant in either an admixed form or applied to the die wall. For this purpose a 40 mm diameter one-piece die was envisaged which would elastically contracted 0.076 mm before compaction and after completion of powder compacting operation, it would be allowed to expand, thus releasing the green compact and so it could be ejected with a force near to weight of the compacts. The experiment indicated that this shrinkage value of 0.076 mm was indeed a realistic estimate which provided sufficient shrinkage to cover both:I– The "elastic die deformation of 40 mm diameter during compaction" which shows 0.0433mm elastic deformation. II–The "elastic spring back of the specimen of 40 mm diameter" which was 0.0227 mm after completion of compaction and releasing the compaction force.Also provided sufficient clearance of 0.010mm between the compact and the die wall on release of compacting pressure to allow ejection of compact with a force near to weight of compact while no lubricant was used on the die wall nor admixed with powder

Evaluating different scenarios for optimizing energy consumption to achieve sustainable green building in Malaysia

One of the most users of energy in the construction industry is residential buildings that use the high value of energy. Because of the high effect of construction activities on environment, serious attention should be given to sustainability concept in construction activities. There are climate factors such as temperature, humidity and pressure that have a considerable effect on the sustainability of green buildings based on energy consumption. The main goal of this paper is to achieve a sustainable green building by optimizing the energy consumption based on two significant factors which are temperature and humidity. To achieve this goal, the design of experiments (DOE) and building simulation are applied. A two-storey house in Malaysia was selected as the case study. The final result shows that to achieve the optimum value of cooling load to have a sustained design of green residential buildings all the significant factors should be placed on a low level which it means that temperature and humidity should be equal to 20 degrees Celsius and 60% respectively

Abelian Higgs model in power-law inflation: the propagators in the unitary gauge

We consider the Abelian Higgs model in the broken phase as a spectator in cosmological spaces of general $D$ space-time dimensions, and allow for the condensate to be time-dependent. We fix the unitary gauge using Dirac's formalism for constrained systems, and then quantize the gauge-fixed system. Vector and scalar perturbations develop time-dependent masses. We work out their propagators assuming the cosmological background is that of power-law inflation, characterized by a constant principal slow-roll parameter, and that the scalar condensate is in the attractor regime, scaling as the Hubble rate. Our propagators correctly reduce to known results in the Minkowski and de Sitter space limits. We use the vector propagator to compute the equal-time correlators of electric and magnetic fields and find that at super-Hubble separations the former is enhanced, while the latter is suppressed compared to the vacuum fluctuations of the massless vector field. These correlators satisfy the hierarchy governed by Faraday's law.Comment: 58 pages + appendices, 2 figures, 2 tables; published versio

Marginal Adaptation of New Bioceramic Materials and Mineral Trioxide Aggregate: A Scanning Electron Microscopy Study

Introduction: This study aimed to compare the marginal adaptation of new bioceramic materials, EndoSequence Root Repair Material (ERRM putty and ERRM paste), to that of mineral trioxide aggregate (MTA) as root-end filling materials. Materials and Methods: Thirty-six extracted human single-rooted teeth were prepared and obturated with gutta-percha and AH-26 sealer. The roots were resected 3 mm from the apex. Root-end cavities were then prepared with an ultrasonic retrotip. The specimens were divided into three groups (n=12) and filled with MTA, ERRM putty or ERRM paste. Epoxy resin replicas from the resected root-end surfaces and longitudinally sectioned roots were fabricated. The gaps at the material/dentin interface were measured using scanning electron microscope (SEM). Transversal, longitudinal, and overall gap sizes were measured for each specimen. The data were analyzed using the Kruskal-Wallis test. Results: In transversal sections, no significant difference was found between MTA, ERRM putty and ERRM paste (P=0.31). However, in longitudinal sections, larger gaps were evident between ERRM paste and dentinal walls compared to MTA and ERRM putty (P=0.002 and P=0.033, respectively). Considering the overall gap size values, the difference between three tested materials was not statistically significant (P=0.17). Conclusion: Within the limits of this study, the marginal adaptation of ERRM paste and putty was comparable to that of MTA. However, ERRM putty might be more suitable for filling the root-end cavities because of its superior adaptation compared to ERRM paste in longitudinal sections