Preparation and Study of Charge Transfer Complexes of N.N.N.N-Tetra-Methyl-Para-Phenylene-Diamine (TMPD) with NG, Tetryl, RDX and HMX

Charge transfer complexes of NG tetryl, RDX and HMX as electron acceptors with tetra-methyl-para-phenylene-diamine (TMPD) as electron donor were prepared and studied. When the solution of nitro-explosives in an inert solvent were added to a solution of TMPD, an intense violet colour was produced. This colour is due to the formation of TMPD cation known as Wurster radical formed from TMPD through the loss of an electron. It has been shown that one mole of each of NG, tetryl, RDX and HMX is needed to form oneTMPD cation. These complexes have also been studied by ultra-violet and infrared spectroscopy

CAN KIDS LEARN BY THEMSELVES USING TECHNOLOGY AND WHAT DO THEY LEARN?

This study presents the method and results of an experiment conducted to investigate whether kids (5-8 years) can use technology to learn in such unsupervised learning conditions. This study also assesses the skills and understanding that children develop through unsupervised technology exposure. The study, carried over 6 months, focused on two primary schools (School ‘A’ and School ‘B’) both found in Mauritius. Both quantitative and qualitative approaches were adopted to collect data for this investigation. The qualitative data focused on interviews with kids, examination of the students’ work on PCs, observation in their ability to explore an interface, use a mouse, keyboard and the Internet. The quantitative data provide information which is easy to analyze statistically and fairly reliable. Descriptive statistics and charts have been used to analyze the quantitative data. It has been found that kids who had access to computers and Internet-based resources both at school and at home can self – educate themselves, but only to some extent because there will come such a moment when they will need a facilitator for guidanc

Magneto-transport studies on (Pr1/3Sm2/3)2/3A1/3MnO3 (A = Ca, Sr and Ba) compounds

Magnetic and transport properties of (Pr1/3Sm2/3)2/3A1/3MnO3 (A = Ca, Sr and Ba) compounds, prepared by the citrate gel route, have been investigated. These compounds are found to crystallize in the orthorhombic structure. Charge ordering transport behavior is indicated only in Ca-substituted compound. The Sr- and Ba-substituted compounds show metal-insulator transition and semiconducting-like behavior, respectively. The magnetoresistance is highest in the Ba substituted compound. All the three samples show irreversibility in magnetization as a function of temperature in zero-field cooled (ZFC) and field cooled (FC) plots. The non-saturating magnetization, even at 5K and 4 Tesla field, are observed in Ca as well Ba-substituted compounds.Comment: Total 23 pages of text and figure

Refractive indices, density and order parameter of some technologically important liquid crystalline mixtures

Temperature variation of the refractive indices, birefringence, density and order parameter of liquid crystalline mixtures E7, E8, N10 and PCH-1132 are reported. The birefringence of PCH-1132 is found to be abnormally low compared to other mixtures

Physical Learning Environment Challenges in the Digital Divide: How to Design Effective Instruction during COVID-19?

The coronavirus disease of 2019 (COVID-19) pandemic has changed the way we work, learn, and interact with others in society. Academic institutions have responded to the pandemic by shifting face-to-face teaching to online instruction. However, whether online instruction succeeds also depends on students’ social and physical learning environment, particularly in developing countries. In this paper, we discuss how learning space challenges exacerbate the digital divide. We argue that weak digital infrastructure, combined with family and social dynamics, create learning space inequality that negatively influence learning outcomes. We provide recommendations on how academic institutions can reimagine content delivery, evaluation, and student support to mitigate learning space inequalities

Refractive indices, density and order parameter of some liquid crystals

The temperature variation of the refractive indices (no, ne) and density are reported for two liquid crystals. The order parameter is evaluated by both Vuks' and Neugebauer's approaches. The possible sources of error in evaluating the order parameter from refractive indices measurements have been discussed. The contradictory behavior of Δ n and ΔX during the nematic-smectic B phase transition of HBT has been explained on the basis of polydomain formation and the order parameter in the SB phase is estimated. The order parameter of two liquid crystals, HBT and OBT, is also evaluated by NMR measurements, confirming the polydomain formation in the SB phase of HBT

Refractive indices, density and order parameter of two liquid crystals HBT and OBT

The temperature variation of refractive indices (ne ne), birefringence (δn), density (ρ) and order parameter (S) of two liquid crystals, namely, N-(p-hexyloxybenzylidene)-p-toluidine (HBT) and N-(p-octyloxybenzylidene)-p-toluidine (OBT) are reported in the smectic (SA in OBT and SB in HBT), nematic and isotropic phases. For accurate measurement of δn, the wedge method was modified to eliminate the need to measure the wedge angle. Density measurements indicate that the smectic-nematic and nematic-isotropic phase transitions in these materials are of first order. Using refractive index values and the density data, the internal field factors (γe, γo), the ratio of principal polarizabilities f(=αeαo) and the order parameter, S, have been evaluated and their temperature dependence discussed in the light of molecular geometry. The order parameter has been determined using the isotropic internal field model (Vuks approach) and the anisotropic internal field model (Neugebauer's approach). The S values determined using these two models agree in the nematic phase but differ considerably in the smectic phase

Post operative wound infection: a descriptive study

Background: Surgical site infections is the third most commonly reported nosocomial infection which has an adverse impact on the hospital as well as the patient. This study was designed to evaluate the frequency, clinical presentation, common risk factors and different organisms involved. Methods: This study was performed at NRI Medical college, Chinnakakani. This is an Observational descriptive study over a period of one year from September 2022 to September 2023. Biodata of the patients together with their clinical features, diagnosis, type of surgery performed and the development of any complications including wound infection was noted and the data analyzed. Results: Out of 1509 patients in the study, 1101 belonged to obstetrics and 408 to gynaecology surgery. The overall incidence of surgical site infection in the study was 7.9%; 86 (7.8%) in obstetrics group and 33 (8%) in gynaecology group developed infection. Age more than 50 years was found to be a risk factor for postoperative wound infection. Obesity is known to be a well-established risk factor for postoperative wound infection. It was noted that surgical site infection was more common in patients that had low haemoglobin levels pre-operatively.  The increased susceptibility to infection in diabetics is an established risk factor. Conclusions: Meticulous surgical technique, proper sterilization, judicious use of antibiotics, improvement of ward environments, control of malnutrition and obesity, treatment of infective foci and diseases like diabetes helps control the morbidity of surgical wound infections