Current Algebra of Super WZNW Models

We derive the current algebra of supersymmetric principal chiral models with a Wess-Zumino term. At the critical point one obtains two commuting super Kac-Moody algebra as expected, but in general there are intertwining fields connecting both right and left sectors, analogously to the bosonic case. Moreover, in the present supersymmetric extension we have a quadratic algebra, rather than an affine Lie algebra, due to the mixing between bosonic and fermionic fields since the purely fermionic sector displays a Lie algebra as well.Comment: 13 page

Mechanical Properties of Eco-friendly Concrete Made with Sugarcane Bagasse Ash

Modern concretes lay emphasis on high strength in order to reduce structural member sizes to reduce materials used; high early strength to promote fast construction; high durability to reduce maintenance costs; and the incorporation of industrial and agricultural wastes to reduce environmental degradation. The incorporation of industrial and agricultural wastes into concrete as cement replacement materials reduces the amount of cement used in the production of concrete and the CO2emissions arising from cement production. Sugarcane bagasse is a waste product from the extraction of juice from sugar cane. It is estimated that 1.7 million tons of bagasse are produced worldwide every year. Much of the bagasse is used as boiler fuel and to produce electricity, and the ash is dumped in earth fills, resulting in critical environmental pollution that requires immediate attention. Available literature shows that when burned under controlled conditions, a pozzolanic ash of high silica content can be obtained, which can be used in concrete production with several advantages. This study investigates the mechanical properties of concrete designed for high strength and incorporating processed sugarcane bagasse ash in amounts of 10–40% by weight of cement in a binary combination with silica fume. Concrete workability in the fresh state and compressive, flexural, and tensile strengths in the hardened state are investigated. Water absorption of hardened concrete is also investigated as an indicator of potential durability. The results show that the mix containing 10% SCBA has the highest mechanical strength, and increasing the SCBA percentage reduces water absorption. However, the workability of concrete in the fresh state reduces substantially with an increase in ash content. Doi: 10.28991/CEJ-2022-08-06-010 Full Text: PD

Solving Multi-Objective Linear Fractional Programming Problems by Novel Methods

في هذا البحث، استخدمنا طريقتين جديدتين لتحويل مسائل البرمجة الجزئية الخطية متعددة الأهداف إلى المسائل البرمجة الخطية الجزئية ذات هدف واحد (SOLFPP) ثم حلها بطرق SOLFPP. يتم تقديم أمثلة عددية توضيحية لهذا الغرض. أيضا، يتم مقارنة النتائج تم الحصول عليها مع طريقة أخرى تمت دراستها سابقاً.In this paper, we suggested two new techniques for transforming multi-objective linear fractional programming problems into single-objective linear fractional programming problems (SOLFPP) and then solving them by methods of SOLFPP. Illustrative numerical examples are presented for demonstration purposes. Also, the obtained results are compared with another method studied previously.&nbsp

Integrable models: from dynamical solutions to string theory

We review the status of integrable models from the point of view of their dynamics and integrability conditions. Some integrable models are discussed in detail. We comment on the use it is made of them in string theory. We also discuss the Bethe Ansatz solution of the SO(6) symmetric Hamiltonian with SO(6) boundary. This work is especially prepared for the seventieth anniversaries of Andr\'{e} Swieca (in memoriam) and Roland K\"{o}berle.Comment: 24 pages, to appear in Brazilian Journal of Physic

PMUTs Arrays for Structural Health Monitoring of Bolted-Joints

Micro-electro-mechanical systems (MEMS) have enabled new techniques for the miniaturization of sensors suitable for Structural Health Monitoring (SHM) applications. In this study, MEMS-based sensors, specifically Piezoelectric Micromachined Ultrasonic Transducers (PMUT), are used to evaluate and monitor the pre-tensioning of a bolted joint structural system. For bolted joints to function properly, it is essential to maintain a suitable level of pre-tensioning. In this work, an array of PMUTs attached to the head and to the end of a bolt, serve as transmitter and receiver, respectively, in a pitch-catch Ultrasonic Testing (UT) scenario. The primary objective is to detect the Change in Time of Flight (CTOF) of the acoustic wave generated by the PMUT array and propagating along the bolt’s axis between a non-loaded bolt and a bolt in service. To model the pre-tensioning of bolted joints and the transmission of the acoustic wave to and from a group of PMUTs through the bolt, a set of numerical models is created. The CTOF is found to be linearly related to the amount of pre-tensioning. The numerical model is validated through comparisons with the results of a preliminary experimental campaign

Remarks on Screening in a Gauge-Invariant Formalism

In this paper we display a direct and physically attractive derivation of the screening contribution to the interaction potential in the Chiral Schwinger model and generalized Maxwell-Chern-Simons gauge theory. It is shown that these results emerge naturally when a correct separation between gauge-invariant and gauge degrees of freedom is made. Explicit expressions for gauge-invariant fields are found.Comment: 13 pages, 1 figure, to appear in PR

Anomalous Soft Photons in Hadron Production

Anomalous soft photons in excess of what is expected from electromagnetic bremsstrahlung have been observed in association with the production of hadrons, mostly mesons, in high-energy (K+)p, (pi+)p, (pi-)p, pp, and (e+)(e-) collisions. We propose a model for the simultaneous production of anomalous soft photons and mesons in quantum field theory, in which the meson production arises from the oscillation of color charge densities of the quarks of the underlying vacuum in the flux tube. As a quark carries both a color charge and an electric charge, the oscillation of the color charge densities will be accompanied by the oscillation of electric charge densities, which will in turn lead to the simultaneous production of soft photons during the meson production process. How the production of these soft photons may explain the anomalous soft photon data will be discussed. Further experimental measurements to test the model will be proposed.Comment: 19 pages, 2 figures, to be published in Physical Review

Reproductive and lactation performance of Kenana and Butana crossbred cows, Gezira State, Sudan

Kenana and Butana cattle are the main indigenous dairy breeds in the Sudan. However, their productive performance is generally low compared to exotic breeds. This necessitates the crossbreeding with high milk producing breeds to meet the increasing demand for milk and dairy products through improving the genetic potential of the indigenous dairy cattle breeds. The objectives of this study were to determine the overall performance of Kenana and Butana 50% crosses with Friesian bulls, to estimate selected reproductive and lactation traits and to study the effects of dam breed, parity, lactation number, season and year of calving on those traits. A total number of 120 records for 30 dairy cows, each for four lactation seasons were used. Data were collected from the master records of Elbashaier dairy farm, about 10 km south of Wadmedani. They covered the years 1990- 2005. The overall means of crossbred dairy cows (days) for age at first calving, calving interval, open period, dry period and lactation period were 970, 400, 122, 65 and 332, respectively. Lactation, daily and standard yields (kg) were 3771, 12 and 3505, respectively. Kenana crossbred cows had higher calving interval, open, dry, lactation periods and lactation yield. Butana crossbred cows had higher age at first calving, daily and standard lactation yields. However, the effect of dam breed was not significant. Dam parity had significant effects (P≤0.05) on all traits except dry period. Age at first calving increased gradually while calving interval and lactation period decreased gradually with parity. Lactation yield was higher in the first and second parities, and daily and standard lactation yields were higher in the fourth parity. Lactation number had significant effects (P≤0.05) on all traits, except open period. Lactation period was higher in the first lactation, while dry period, lactation, daily and standard yields were least in the first lactation and increased with advanced lactation. Season of calving had significant effects (P≤0.05) on calving interval, open period, daily and standard lactation yields. Calving interval, open and lactation periods were longer, while, daily and standard lactation yields were lower during winter. Year of calving had significant effects (P≤0.05) on all traits except dry period. Age at first calving increased gradually with age

Antibacterial Activities of Yansoon (Pimpinella anisum L.), Ginger (Zingiber officinale L.) and Cinnamon (Cinnamomum zeylanicum L.) Extracts

There is an increasing demand for the biologically active substances from plant origin which is of current interest and focus for new research approach. The synthetic pharmaceuticals compounds showed various side effects on functions of different parts of the human body, both internally and externally. Therefore, the present study was investigating the antimicrobial activity of three important herbs, Ginger (Zingiber officinale L.), Yansoon (Pimpinella anisum L.) and Cinnamon (Cinnamomum zeylanicum L.). The cup- plate agar (inhibition zone) method was used for studying the effects of the extracts against Streptococcus sp, Staphylococcus aureus and  Enterococcus faecalis. The results showed that, the ethanol extracts of cinnamon and the combination of ginger and cinnamon were highly effective on Streptococcus sp (24mm and 21mm, respectively), compared to the water extracts (15mm and16mm, respectively). However, the water and the ethanol extracts of ginger and yansoon were less effective (11mm, 9mm, 8.5mm and 8mm, respectively). The ethanol extracts of cinnamon and the combination of ginger and cinnamon were highly effective on Staphylococcus aureus giving (24mm and 21.5 mm, respectively) followed by water extract (20mm and 21 mm, respectively). While, the ethanol and water extracts of ginger and yansoon were less effective (11mm, 10.5mm, 9mm and 9.5mm, respectively). The ethanol and water extracts of cinnamon were highly effective on E. faecalis giving (21mm and 20.5 mm, respectively). The ethanol extracts of the combination of ginger and cinnamon were effective (20 mm) followed by water extract (18mm). The water and ethanol extracts of ginger and yansoon were less effective giving (15 mm, 12 mm, 8 mm and 9 mm, respectively). From the results it could be concluded that, the extracts of (Cinnamon, Yansoon and Ginger) can be used as antimicrobial agents. It could be suggested that the active antimicrobial components need to be verified in any further study and more microorganism are to be tested                                                                                          . &nbsp