Photoinitiated coupling of dienes and monoolefins with pentacarbonyliron

The photoreaction of pentacarbonyliron with 1,3-diene/monoolefin mixtures results in C-C coupling of the two organic substrates, forming a six-carbon chain which is coordinated to the Fe (CO) 3 moiety in a 1-a,4-6-n3 fashion. Using various 1,3- dienes and monoolefins carrying methyl and carboalkoxy substituents, the wide applicability of this process is demonstrated

Mine Action in North Sudan

North Sudan’s National Mine Action Centre is making great strides toward clearing all known mined areas in Sudan’s northern regions by April 2014. In the following article, the author, a Quality Assurance Officer for NMAC, explores NMAC’s work, future plans, and how it has linked mine action to development and recovery in North Sudan

The Stretch-Engine: A Method for Creating Exaggeration in Animation Through Squash and Stretch

Animators exaggerate character motion to emphasize personality and actions. Exaggeration is expressed by pushing a character’s pose, changing the action’s timing, or by changing a character’s form. This last method, referred to as squash and stretch, creates the most noticeable change in exaggeration. However, without practice, squash and stretch can adversely affect the animation. This work introduces a method to create exaggeration in motion by focusing solely on squash and stretch to control changes in a character’s form. It does this by displaying a limbs' path of motion and altering the shape of that path to create a change in the limb’s form. This paper provides information on tools that exist to create animation and exaggeration, then discusses the functionality and effectiveness of these tools and how they influenced the design of the Stretch-Engine. The Stretch-Engine is a prototype tool developed to demonstrate this approach and is designed to be integrated into an existing animation software, Maya. The Stretch-Engine contains a bipedal-humanoid rig with controls necessary for animation and the ability to squash and stretch. It can be accessed through a user interface that allows the animator to control squash and stretch by changing the shape of generated paths of motion. This method is then evaluated by comparing animations of realistic motion to versions created with the Stretch-Engine. These stretched versions displayed exaggerated results for their realistic counterparts, creating similar effects to Looney Tunes animation. This method fits within the animator’s workflow and helps new artists visualize and control squash and stretch to create exaggeration

Detection of Methicillin-resistant and Biofilm-producing Staphylococcus aureus in Bovine Mastitis

The present study was employed to investigate the causative microorganisms responsible for clinical and subclinical mastitis and their antibiotic susceptibility pattern on a private cow farm in Assiut Governorate, Egypt, where a history of recurrent mastitis was the main complaint. In addition, the isolates were investigated for their ability to form biofilm. Forty cows were subjected to a physical examination of the udder and milk using the California mastitis test. Additionally, milk sample collections were obtained, and bacterial specimens were isolated and evaluated for the presence of the mecA gene by PCR. Antibacterial susceptibility assays against the common antibiotics used in the veterinary field were conducted for all isolates obtained. Furthermore, biofilm production by bacterial isolates was detected using the microtiter plate method (MTP) and the activity of specific antibiotics was evaluated against preformed biofilms. About 10% of the examined cows showed clinical signs of mastitis, and 22.2% revealed subclinical mastitis infection when evaluated via the California mastitis test. Staphylococcus aureus (S. aureus) was isolated from all mastitic cows, which indicated that it was the main causative organism for the infection. Streptococcus spp. were isolated from six mastitic animals. Half of the S. aureus isolates were methicillin-resistant, and 83.33% of them were capable of producing biofilm. All Streptococcus spp. isolates were sensitive to all the antibiotics evaluated in the study. S. aureus isolates in the planktonic form were resistant to oxytetracycline and penicillin. In contrast, S. aureus encased in biofilm were resistant to all the antibiotics used in the study. This research detected highly-virulent S. aureus isolates from clinical and subclinical mastitic cases that carry the mecA gene and produce biofilm. The owner is advised to cull the diseased cows to prevent the spread of these virulent isolates to healthy animals. Also, it is advisable not to treat the diseased cows with the antibiotics evaluated in this study as they were found to be ineffective and may potentially contribute to persistence of the infection

The Marble Industry in Egypt: A Microeconomic Analysis

This thesis presents a microeconomic assessment of the marble industry in Egypt. It starts with an overview and analysis of the international marble industry, highlighting this industry as one of the oldest industries in the world. Historically, the industry moved from labor­intensive to capital-intensive with the advent of technological advancement, including development of automated production tools like cranes and diamond cutting wires. In Egypt, during the past 20 years, market entry into the industry was high, due to the high profit margins achieved. In addition, there was (and still is) lack of effective government regulation. Currently, the marble industry in Egypt could be described as that of monopolistic competition, where products are highly differentiated and there are relatively small barriers to entry. However, barriers to entry are becoming more tangible as the needed capital investment increased sharply with the devaluation of the Egyptian Pound. In order to study the dynamics of the industry more thoroughly, a case study (Watany Marble) was examined from two microeconomic perspectives: (1) an investment appraisal using economic cost-benefit analysis leading towards NPV, IRR, ERR and ROI calculations; and (2) application of the theory of the firm to the case study using Cobb Douglas production, profit maximization, cost minimization and returns to scale calculations. Results yield a ROI of 12.24% using weighted­average opportunity cost of capital considerations, a declining long-run average cost curve, and increasing returns to scale in production. Using isoquant-isocost analysis, the marginal rate of technical substitution between factors of production resulted in $ 1000 of capital corresponding to 7.5 units of labor. Future prospects for the industry is market segmentation, where value-driven and export-oriented firms will tend towards forming an oligopoly, whereas local-oriented, cost-driven firms with relatively low technology will tend towards operating under conditions of a monopolistic competition

Computational Modelling of Thermal Transport using Spectral Phonon Boltzmann Transport Equation

Lattice vibration is the main microscopic mechanism for thermal transport in dielectric materials. The convenience of the analysis of atomic vibrations in the reciprocal space, motivated by the pioneering work of Debye and Peirels, made phonon transport theory is one of the standard paradigms adequate to study the microstructure and stoichiometry effects on thermal transport phenomena at mesoscale. UO2 is of theoretical as well as technological importance. The characteristic thermal transport phenomena at short length-scale (~ nanometer) and time-scale (~ picosecond) associated with radiation dictate close examination of available theoretical models and solution methods for thermal conductivity prediction, in addition to the validity of introduced approximations. By the virtue of INS experimental technique with powerful resolution, a direct benchmarking of simulated phonon properties results has been made possible. This provides by far a more accurate assessment criteria than thermal conductivity, and pave the way for founding sophisticated models of radiation effects on thermal transport with theoretical supports, beyond the currently available empirical or phenomenological models that succeed to reproduce the right macroscopic behavior in many cases just because of error cancellations and/or the use of adjustable parameters. Within time dependent perturbation theory (Fermi golden rule) framework, to represent the collision term of the semi-classical phonon Boltzmann Transport Equation, the bottleneck of the employed approach is to calculate intrinsic and extrinsic scattering rates of phonon modes. Being a highly correlated system with 5f electrons and magnetic phase transition at very low temperature, there are several challenges facing first-principle methods to leverage accurate phonon properties at finite temperature and imperfect structure that still need to be overcome. Moreover, it is common that using 3-phonon processes alone in other dielectrics overestimates lattice thermal conductivity at high temperatures (due to ignoring higher order phonon-phonon interactions), however, previous computational studies predicted values for UO2 conductivity lower than experiment by a factor of two about one third of the melting temperature. These observations assert the necessity of firstly investigating the impact of different introduced approximations for the calculation of intrinsic lattice thermal conductivity, to analyze the crucial parameters and to better understand this anomalous prediction. In this investigation, we present a critical assessment of several common approximations for the calculations of lattice thermal conductivity using spectral phonon Boltzmann Transport Equations. These approximations pertain to dispersion anisotropy and relations, Brillouin zone structure, and the coupling between the scattering rates of phonon normal modes. By employing harmonic approximation—perturbation theory to describe the scattering rates of a model system, FCC argon, our calculations show that widely spread approximations such as isotropic continuum and Single Mode Relaxation Time (SMRT) are not reliable, even for the case of cubic systems with their high symmetry properties. The success of these approximations is demonstrated to be a direct result of error cancellations. In addition, we show the essential importance of considering coupling terms at phonon mode level, and not in a statistical average sense as, for example, Callaway’s model does. By taking into account the coupling terms, the results evidence the crossover between the heat diffusion mediated by particle-like phonons (incoherent scattering) and the wave-like heat propagation due to phonon coherent scattering. Furthermore, this made possible revealing thermal conductivity anisotropy in cubic crystals. Finally, sensitivity of conductivity prediction to phonon spectrum is found to change over temperature. On the other hand, we challenge the widespread consensus that phonon-phonon interactions are inactive in the low temperature regime, which, in past investigations, led to the belief that the peak in lattice thermal conductivity (versus temperature) occurs because of two competing scattering mechanisms, umklapp and defect scattering mechanisms, dominant above and below the peak temperature, respectively. To the contrary, our study demonstrates that peak thermal conductivity, versus temperature, can still be obtained solely based upon phonon-phonon processes. This finding has been aided by considering the inelastic nature of 3-phonon scattering through applying energy conservation rule in a statistical average sense. Among the different statistical distributions examined to represent the regularized Dirac delta function appearing in Fermi Golden Rule, adopting Lorentz distribution, in analogy with phonon normal mode eigenenergy broadening due to the leading term of crystal anharmonicity, can uniquely reproduce the attained behavior in the low temperature limit. Simulation results, based on our adjustable parameter-free model, evidence that the heavy tail of the Lorentz distribution is the key. Unlike other models that similarly employ harmonic approximation—perturbation theory to describe the 3-phonon scattering rates, a maximum in the intrinsic thermal conductivity at finite temperature was strikingly obtained in our investigation, without the need to consider multi-step or higher order phonon interactions. By applying our approach to solid argon, considering only three-phonon scattering, good agreement with experiment was achieved for the first time in both the low (T2) and high (T-1) temperature regimes simultaneously, in addition to the peak temperature (~ 8 K). This indicates that phonon-phonon interactions can solely be used to interpret the shape of the conductivity versus temperature curve for the case of Ar, without the need to invoke defect or boundary scattering in the low temperature regime. At the same time, by employing the same computational model for UO2, the results show that phonon-phonon interactions are not predominant in the sub-peak regime, which suggest that phonon-magnon interactions should be considered at low temperature to reproduce experimental results