Zeroing in on more photons and gluons

We discuss radiation zeros that are found in gauge tree amplitudes for processes involving multi-photon emission. Previous results are clarified by examples and by further elaboration. The conditions under which such amplitude zeros occur are identical in form to those for the single-photon zeros, and all radiated photons must travel parallel to each other. Any other neutral particle likewise must be massless (e.g. gluon) and travel in that common direction. The relevance to questions like gluon jet identification and computational checks is considered. We use examples to show how certain multi-photon amplitudes evade the zeros, and to demonstrate the connection to a more general result, the decoupling of an external electromagnetic plane wave in the ``null zone". Brief comments are made about zeros associated with other gauge-boson emission.Comment: 26 page

Asymptotic Pad\'e Approximants and the SQCD β\beta-function

We present a prediction for the four loop $\beta$-function for SQCD based on the method of Asymptotic Pad\'e Approximants.Comment: 8 pages, including 2 figures. Plain TeX. Uses Harvmac and eps

Effect of strontium and cooling rate upon eutectic temperatures of A319 aluminum alloy

DTA analysis was used to investigate the solidification reactions of alloy A319 with either 12 or 136 ppm of Sr added. Strontium does not affect primary solidification of (Al) dendrites but modifies the kinetics of the (Al)–Si eutectic. The effects of Sr level and of cooling rate on the characteristic temperatures for the (Al)–Si and other eutectic reactions are described

Employee Engagement, Organisational Commitment and Performance of Selected State Corporations in Kenya

The influence of employee engagement on organisational performance has been widely acknowledged and confirmed. However, there are scanty empirical investigations on the mediating role of organisational commitment on the relationship between employee engagement and organisational performance. Therefore, this study sought to investigate the mediating influence of organisational commitment on the relationship between employee engagement and performance of selected state corporations in Kenya. The study adopted a positivistic approach to investigate the relationships among and between the variables. Descriptive and explanatory research designs were used to describe the variables and establish the nature of the relationships among them. The study is based on employees of state corporations in research and training in the republic of Kenya. A sample of 378 respondents was selected using a multi stage sampling strategy. Data was analysed using descriptive and inferential statistics. The result indicates that employee engagement influences organisational performance and that the relationship is partially moderated by organisational commitment

Development of a constitutive model for the compaction of recovered polyethylene terephthalate packages

[EN] To date, PET (polyethylene terephthalate) is the most widely used plastic in packaging and also one of the most recycled polymers worldwide. However, the high transport costs and stagnated prices of recycled PET undermine recycling process profits. Transport costs can lower through compaction, which is still not a completely wellknown process. Due to heterogeneous designs, the output density of the compaction process varies. This poses problems during equipment design, selection or operation processes as recovery costs sharply increase if the required density is not met. In this manuscript, the authors develop a constitutive model for the compaction of recovered PET packaging. This experimentally validated model, based on the elasto-plastic behaviour of PET packages, allows the output density range to be predicted according to the compression pressure during PET compaction. Unlike other generic compaction models that need more than two parameters, this model uses only one and better correlates with the experimental results. Unlike existing generic models, the model parameters have a physical meaning, which allows the influence of different factors on the compaction process to be assessed. Finally as a result of the model analysis, we provide some tips to enhance compaction equipment efficiency.Funding for open access charge: CRUE-Universitat Politecnica de Valencia.Sanchez-Caballero, S.; Sellés, M.; Peydro, MA.; H.P. Cherukuri (2021). Development of a constitutive model for the compaction of recovered polyethylene terephthalate packages. Waste Management. 133:89-98. https://doi.org/10.1016/j.wasman.2021.07.028S899813

Lithium Sulfonate Functionalization of Carbon Cathodes as a Substitute for Lithium Nitrate in the Electrolyte of Lithium–Sulfur Batteries

A method for grafting lithium sulfonate (LiSO3) groups to carbon surfaces is developed and the resulting carbons are evaluated for their potential to reduce the lithium polysulfide (LiPS) shuttle in lithium–sulfur (Li–S) batteries, replacing the common electrolyte additive lithium nitrate (LiNO3). The LiSO3 groups are attached to the ordered mesoporous carbon (CMK3) surface via a three-step procedure to synthesize LiSO3-CMK3 by bromomethylation, sodium sulfite (Na2SO3) substitution, and cation exchange. As a comparison, ethylenediamine (EN)-substituted CMK3, EN-CMK3, is also synthesized and tested. When used as a cathode in Li–S batteries, the unfunctionalized CMK3 suffers from strong LiPS shuttling as evidenced by its low initial Coulombic efficiencies (ICEs, <10%) compared to its functionalized derivatives EN-CMK3 and LiSO3-CMK3 (ICEs >75%). Postcycling analysis reveals the benefits of cathode surface functionalization on the lithium anode via an attenuated LiPS shuttle. When monitored at open circuit, the functionalized cathodes maintain their cell voltages much better than the CMK3 control and concurrent electrochemical impedance spectroscopy reveals their higher total cell resistance, which provides evidence for a reduced LiPS shuttle in the vicinity of both electrodes. Overall, such surface groups show promise as cathode-immobilized “lithium nitrate mimics.”

Use of a Novel Polymer-Coated Steel as an Alternative to Traditional Can Manufacturing in the Food Industry

[EN] Metal containers (both food and beverage cans) are made from huge steel or aluminum coils that are transformed into two- or three-piece products. During the manufacturing process, the metal is sprayed on both sides and the aerosol acts as insulation, but unfortunately produces volatile organic compounds (VOCs). The present work presents a different way to manufacture these containers using a novel prelaminated two-layer polymer steel. It was experimentally possible to verify that the material survives all the involved manufacturing processes. Thus tests were carried out in an ironing simulator to measure roughness, friction coefficient and surface quality. In addition, two theoretical ironing models were developed: upper bound model and artificial neural network. These models are useful for packaging designers and manufacturers.Sellés, M.; Schmid, SR.; Sanchez-Caballero, S.; Ramezani, M.; Pérez Bernabeu, E. (2021). Use of a Novel Polymer-Coated Steel as an Alternative to Traditional Can Manufacturing in the Food Industry. Polymers. 13(2):1-15. https://doi.org/10.3390/polym13020222S11513

Tops and Writhing DNA

The torsional elasticity of semiflexible polymers like DNA is of biological significance. A mathematical treatment of this problem was begun by Fuller using the relation between link, twist and writhe, but progress has been hindered by the non-local nature of the writhe. This stands in the way of an analytic statistical mechanical treatment, which takes into account thermal fluctuations, in computing the partition function. In this paper we use the well known analogy with the dynamics of tops to show that when subjected to stretch and twist, the polymer configurations which dominate the partition function admit a local writhe formulation in the spirit of Fuller and thus provide an underlying justification for the use of Fuller's "local writhe expression" which leads to considerable mathematical simplification in solving theoretical models of DNA and elucidating their predictions. Our result facilitates comparison of the theoretical models with single molecule micromanipulation experiments and computer simulations.Comment: 17 pages two figure

Effect of experimental Trypanosoma congolense infection on serum profiles of lipid and cholesterol in pack donkeys

The effect of experimental Trypanosoma congolense (T. congolense) infection on serum concentrations of lipids in donkeys was investigated. To establish the infection, four apparently healthy pack donkeys were, each, intravenously inoculated with blood (1 ml) from an infected donor donkey containing 1 x 106 T. congolense organisms. Following this, 5 ml of blood was collected from each of the experimental animals, starting from day zero and then every other day throughout the experimental period and used for haematological and serum biochemical analyses. Levels of triglyceride, total cholesterol, high density lipoprotein-cholesterol (HDL-cholesterol) and low density lipoprotein-cholesterol (LDL-cholesterol) in the serum were measured over a 28-day experimental period, using commercial test kits. The infection with T. congolense caused significant (P<0.05) decreases in serum concentrations of total cholesterol and LDL-cholesterol in the experimental animals. Decreases were also observed in the serum concentrations of triglyceride and HDL-cholesterol but were not significant (P>0.05). With the indispensable roles of lipids as integral parts of cell membrane structures and in other metabolic processes in the mammalian hosts, it could be inferred that T. congolense infection-induced alterations in serum concentrations of lipids might be contributory pathophysiological mechanisms of some of the reported disorders in trypanosome-infected animals.Keywords: Donkey, Cholesterol, Triglyceride, HDL-cholesterol and LDL-cholesterolTrypanosoma congolens

Research on the Friction Properties of DP600 Stainless Steel as a Function of Bending Angle and Pin Diameter

[EN] The rapid evolution of materials and manufacturing processes, driven by global competition and new safety and environmental regulations has had an impact on automotive structures (Body In White; BIW) manufacturing. The need for lighter vehicles, with more equipment, that are safer and eco-friendly at the same time, relates to the entire life cycle of the car. Car and steelmakers agree that weight reduction is possible, and the solution involves the use of new advanced high-strength steels. Thinner and stronger materials lead to higher demands on stamping, the most used manufacturing in BIW parts. The use of advanced high-strength steels raises new challenges, especially concerning the lubrication between the die and the sheet. To study the lubrication conditions of the stamping process, a sheet metal forming a simulator was developed. The simulator consists of two cylinders that pull the strip of steel and a pin in between. The angle between the cylinders can be adjusted from 0 to 90 degrees, which allows analysis of the effect of the stamping angle. The pull force and velocity can be set and measured, and the peripheric pin velocity, the strain, and the strain velocity can be measured as well. In this work, the tribological properties of Dual-Phase 600 stainless steel using different processing conditions have been analyzed. To this end, a factorial experiments design with twelve parameters that compare the behavior of different angles and diameters was run. The results showed that the friction coefficient increases by increasing the bending angle and decreases with pin diameter.Sanchez-Caballero, S.; Sellés, M.; Pla-Ferrando, R.; Segui Llinares, VJ.; Peydro, MA. (2021). Research on the Friction Properties of DP600 Stainless Steel as a Function of Bending Angle and Pin Diameter. Materials Proceedings. 3(1):1-7. https://doi.org/10.3390/IEC2M-09248173