Biodiversity of fresh water algae from Guindy campus of Chennai, India

The present work deals with the 35 fresh water algal samples and description of 62 taxa of biodiversity of fresh water algae from University of Madras Guindy campus of Chennai. Collections of 35 fresh water algal samples were carried out during the month of December 2010 to April 2011. Samples were examined in the laboratory and identified. The following algae were present Chlorococcum(1), Elakatothrix (1), Chlorella (1), Palmellococcus (1), Tetraedron  (1), Polyedriopsis (1), Chodatella (1), Oocystis (2),  Coelastrum (1), Scenedesmus quadricauda  (Turpin) Breb. var. longispina  (Chodat) G. M. Smith, Scenedesmus (3), Microspora (1), Rhizoclonium (1), Trentipholia  (2), Closterium (1), Cosmarium (5) of Chlorophyceae, Cyclotella (1),  Fragilaria (2),  Achnanthes (1), Amphora (1), Navicula (5), Pinnularia (1), Hantzschia  (1) and Nitzschia (1) of Bacillariophyceae and Microcystis (1), Chroococcus (3)  Chroococcidiopsis (1), Gloeocapsa (2), Gleocapsopsis (1), Aphanotheace (1), Chlorogloea (2), Oscillatoria (3), Phormidium (3), Lyngbya (3), Microcoleus (1), Microchaete tenera (1), Calothrix (1), Camptylonema (1)  and Hapalosiphon (1) of Cyanophyceae were recorded. Algae are described with photographs

Futuristic Perspective Analysis of Online Buyers for Sustainability of E-commerce

In the global competitive business world, utilization of modern and innovative technological practices in business transactions is inevitable. E-commerce is a paradigm shift to connect customers electronically in the present business system. E-commerce covers electronic transmission of information, monetary payments and physical delivery of products. It is a pertinent time to analyse the future potentiality of e-commerce and the perception of online buyers who use this platform. A study was conducted with the following objectives: to describe the perception of online buyers, to make online buyers’ Futuristic Perspective Analysis (FPA) of e-commerce and to study factors influencing sustainability of e-commerce in the future. The data were collected from primary and secondary sources. A primary survey was conducted through structured questionnaire administered on select online buyers in Karaikal, Union Territory of Puducherry, India. The collected data were analysed with multivariate statistical tools like factor analysis and multiple regression analysis with SPSS. The findings were presented with suitable suggestions to know the futuristic perspectives of online buyers and the sustainability of e-commerce

Tribological and mechanical properties of biobased reinforcement in a friction composite material

This work presents the function of biobased ingredients (palm fiber) as reinforcement in brake pad materials. Reinforcement in brake lining improvise wear stability, wear resistance and friction optimization under a dynamic set of operating variables such as braking force, sliding speed, braking duration and braking temperature. The effect of palm fiber on physical, mechanical and tribological properties of brake pad composite is evaluated. The percentage of palm fiber is gradually increased from 2% to 12% at an interval of 2% as an alternate of rockwool fiber by varying the pressure and speed in a pin on disc tribometer. By increasing the pressure, 8% and 10% shows high friction stability at all speeds. The results show that the raise in the palm fiber quantity increases the hardness, specific gravity and heat swell and the properties, loss on ignition and porosity decreases. The SEM descriptions of the composite indicated that the smaller micro voids occurred in the sample having low palm fiber. Weight gain in the composites were also observed by exposing them in salt water, water and oil.Keywords: Palm Fiber, Wear, Friction Stability, Brakes, SEM

Experimental investigations of electrodeposited Zn-Ni, Zn-Co, and Ni-Cr-Co-based novel coatings on AA7075 substrate to ameliorate the mechanical, abrasion, morphological, and corrosion properties for automotive applications

The aluminum (Al) alloy AA7075 is widely used in various industries due to its high strength-to-weight ratio, which is comparable and replaceable to steel in many applications. However, it has poor resistance to wear and corrosion compared to other Al alloys. The conventional pressure die coating with Cr and cadmium has led to premature failure while the load is applied. It is indeed to develop a novel coating method to improve the mechanical, wear, and corrosion properties of AA7075 Al alloy. In the present investigation, the binary and ternary metals such as zinc-nickel (Zn-Ni), zinc-cobalt (Zn-Co), and nickel-chromium-cobalt (Ni-Cr-Co) are electroplated on the substrate material (AA7075). In order to ensure optimal coating adhesion, the surface of the substrate material was pre-treated with laser surface treatment (LST). The mechanical and corrosion studies have been carried out on the uncoated and coated materials. It is observed from the findings that the ternary coating has higher wear resistance than the binary-coated material. The ternary coating has 64% higher resistance in the non-heat-treated status and 67% higher resistance in the heat-treated condition compared to the uncoated specimens. The tensile strength (MPa) of Ni-Cr-Co on AA7075 pressure die casting (PDC) is higher than the other deposits (582.24 of Ni-Cr-Co > 566.07 of Zn-Co > 560.05 of Zn-Ni > 553.64 of uncoated condition). The presence of a crystalline structure with the high alignment of Co and Ni atoms could significantly improve the corrosion resistance of Ni-Cr-Co coatings on AA 7075 PDC substrates when compared to binary coatings. The scanning electron microscopy (SEM) images, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy findings on the coated materials have been corroborated with the analyses on mechanical and corrosion properties. The XRD analysis of the Zn-Ni binary coating has reported that the diffraction peaks of γ-NiZn3 (831), γ-Ni2Zn11 (330), and 631 with 2θ values 38, 43, and 73° are confirming the presence of Zn-Ni binary deposit on AA7075 PDC substrate. The XRD pattern of Zn-Co-coated material has revealed that the presence of three strong peaks such as Zn (110), Co (111), and CoZn (211) and two feeble peaks such as ϵ-CoZn3 (220) and ϵ-CoZn3 (301) are clearly visible. The XRD pattern of Ni-Cr-Co ternary coating has exhibited that the Ni-Cr-Co ternary deposit is a solid solution with a body-centered cubic structure due to the formation peaks at lattice plane such as (110), (220), and (210) with a crystal lattice constant of 2.88 A°. The SEM image for both the binary- and ternary-coated materials has exhibited that the deposited surface has displayed many shallow pits due to hitting by progressive particles. The SEM image has illustrated the presence of Zn-Ni atoms with smaller globular structure. The surface morphology of binary Zn-Co coating on the PDC AA7075 substrate has unveiled the evenly distributed dot-like structure and submerged Co particles in the galaxy of Zn atoms. To understand the effectiveness of bonding by laser texturing, cross-section SEM has been carried out which furthermore revealed the effective adhesion of Ni-Cr-Co on AA7075 PDC; this could also be the reason for the enhancement of microhardness, wear, and corrosion resistance of the said coating. © 2023 the author(s), published by De Gruyter

Synthesis, magnetic and optical properties of core/shell Co1-xZnxFe2O4/SiO2 nanoparticles

The optical properties of multi-functionalized cobalt ferrite (CoFe2O4), cobalt zinc ferrite (Co0.5Zn0.5Fe2O4), and zinc ferrite (ZnFe2O4) nanoparticles have been enhanced by coating them with silica shell using a modified Stöber method. The ferrites nanoparticles were prepared by a modified citrate gel technique. These core/shell ferrites nanoparticles have been fired at temperatures: 400°C, 600°C and 800°C, respectively, for 2 h. The composition, phase, and morphology of the prepared core/shell ferrites nanoparticles were determined by X-ray diffraction and transmission electron microscopy, respectively. The diffuse reflectance and magnetic properties of the core/shell ferrites nanoparticles at room temperature were investigated using UV/VIS double-beam spectrophotometer and vibrating sample magnetometer, respectively. It was found that, by increasing the firing temperature from 400°C to 800°C, the average crystallite size of the core/shell ferrites nanoparticles increases. The cobalt ferrite nanoparticles fired at temperature 800°C; show the highest saturation magnetization while the zinc ferrite nanoparticles coated with silica shell shows the highest diffuse reflectance. On the other hand, core/shell zinc ferrite/silica nanoparticles fired at 400°C show a ferromagnetic behavior and high diffuse reflectance when compared with all the uncoated or coated ferrites nanoparticles. These characteristics of core/shell zinc ferrite/silica nanostructures make them promising candidates for magneto-optical nanodevice applications

New endoperoxides highly active in vivo and in vitro against artemisinin-resistant Plasmodium falciparum

Background: The emergence and spread of Plasmodium falciparum resistance to artemisinin-based combination therapy in Southeast Asia prompted the need to develop new endoperoxide-type drugs. Methods: A chemically diverse library of endoperoxides was designed and synthesized. The compounds were screened for in vitro and in vivo anti-malarial activity using, respectively, the SYBR Green I assay and a mouse model. Ring survival and mature stage survival assays were performed against artemisinin-resistant and artemisinin-sensitive P. falciparum strains. Cytotoxicity was evaluated against mammalian cell lines V79 and HepG2, using the MTT assay. Results: The synthesis and anti-malarial activity of 21 new endoperoxide-derived compounds is reported, where the peroxide pharmacophore is part of a trioxolane (ozonide) or a tetraoxane moiety, flanked by adamantane and a substituted cyclohexyl ring. Eight compounds exhibited sub-micromolar anti-malarial activity (IC50 0.3–71.1 nM), no cross-resistance with artemisinin or quinolone derivatives and negligible cytotoxicity towards mammalian cells. From these, six produced ring stage survival < 1% against the resistant strain IPC5202 and three of them totally suppressed Plasmodium berghei parasitaemia in mice after oral administration. Conclusion: The investigated, trioxolane–tetrazole conjugates LC131 and LC136 emerged as potential anti-malarial candidates; they show negligible toxicity towards mammalian cells, ability to kill intra-erythrocytic asexual stages of artemisinin-resistant P. falciparum and capacity to totally suppress P. berghei parasitaemia in mice.info:eu-repo/semantics/publishedVersio