scholarly journals Nickel Nanoparticles Immobilized on a Porous Triazine-Thiourea-Sulfonamide as an Efficient Heterogeneous Catalyst for Reduction of Carbonyl Compounds

Author(s):  
Abumuslim Rahimi ◽  
Ramin Ghorbani-Vaghei ◽  
Sedigheh Alavinia

Abstract In order to investigate the role of silica template, polymers and nickel nanoparticles on the reduction of aldehydes/ketones, a novel porous triazine-thiourea-sulfonamide polymeric organic support (TTSA) was prepared via in-situ polymerization of melamine (1,3,5-triazine-2,4,6-triamine), thiourea and benzene-1,3-disulfonyl chloride in the presence of silica nanoparticles as a template led to the synthesize silica TTSA nanocomposite. Next, after removal of the template, the nanocomposite was transformed into mesoporous poly triazine-thiourea-sulfonamide. Ni nanoparticles (Ni NPs) were then decorated on the designed mesoporous polymer support and the resulting TTSA@Ni NPs nanospheres were employed as heterogeneous catalyst in the construction of alchohols from reduction of aldehydes/ketones using formic acid/triethyl amine as a reducing agent in water as solvent. The catalyst is low-cost, non-toxic, and can be reused for several catalytic cycles without decreasing the activity.

Author(s):  
Anjana Srivastava ◽  
P. C. Srivastava

In soil, pesticide residues are subjected to various transformations and transportation processes. Leaching is one of the major transportation processes responsible for ground water contamination. Organic amendments used in agriculture are known to improve the physico-chemical properties of soil at low cost and are regarded as one of the most suitable technologies for sustainable agriculture. These amendments play an important role in the retention of pesticides because of increased adsorption of these chemicals on soil. Sorption of pesticides which are weak acids or bases, is influenced by soil pH because they assume a positive or negative charge, or no charge depending on the pH. Leaching of such pesticides to ground water can be prevented to a great extent by mixing of organic amendments to soil because they enhance the ability of pesticide retention on soil and or promote their microbial degradation as well during in situ decomposition of organic amendments in soil.


1998 ◽  
Vol 521 ◽  
Author(s):  
V. Gergely ◽  
T. W. Clyne

ABSTRACTMelt routes to metallic foam production offer attractions of low cost and the potential for good microstructural control. In situ gas generation may be preferable to external gas injection in terms of the important objective of generating a fine and uniform cell structure. The main difficulty with this approach has been that of ensuring that the gas-generating powder is suitably dispersed throughout the melt before the gas is released and the cells are formed.In the present paper, procedures are outlined for preparation of powders for use in aluminium melts, where gas will be released only after a suitable delay, allowing the powders to first become well-dispersed in the melt and solidification to start. Pre-treatment of the foaming agent also facilitates a flexible production of castings with various porosity at the same processing conditions simply by varying the thickness of a diffusion barrier layer on the gas-releasing agent. The role of the melt viscosity history, as a function of a heat extraction rate from the solidifying melt and an alloy composition, on the final porosity of the castings is also briefly discussed.


2019 ◽  
Vol 4 (2) ◽  
pp. 113-120
Author(s):  
M.G. Kukade ◽  
N.L. Gavade ◽  
A.N. Kadam ◽  
W.B. Chandane ◽  
K.M. Garadkar ◽  
...  

In present study, magnetically separable cobalt ferrite nanoparticles (CoFe2O4·NPs) have been prepared by low cost chemical precipitation method and reported as reusable, proficient heterogeneous catalyst for the synthesis of 1-oxo-hexahydroxanthenes among other ferrites. The structural and morphological studies by X-ray diffraction and scanning electron microscopy confirmed the formation of CoFe2O4 nanoparticles. The current protocol evaluated a proficient catalyst for reaction between various salicylaldehydes and 1,3-diketones. The ambient reaction conditions, shorter reaction time, good to excellent yields of the products, ease of purification of the products and reusa-bility of catalyst up to five catalytic cycles without significant loss of catalytic activity making the current protocol promising for its practical application.


Author(s):  
Jian-Shing Luo ◽  
Hsiu Ting Lee

Abstract Several methods are used to invert samples 180 deg in a dual beam focused ion beam (FIB) system for backside milling by a specific in-situ lift out system or stages. However, most of those methods occupied too much time on FIB systems or requires a specific in-situ lift out system. This paper provides a novel transmission electron microscopy (TEM) sample preparation method to eliminate the curtain effect completely by a combination of backside milling and sample dicing with low cost and less FIB time. The procedures of the TEM pre-thinned sample preparation method using a combination of sample dicing and backside milling are described step by step. From the analysis results, the method has applied successfully to eliminate the curtain effect of dual beam FIB TEM samples for both random and site specific addresses.


2020 ◽  
Author(s):  
Nicolò Maria della Ventura ◽  
Szilvia Kalácska ◽  
Daniele Casari ◽  
Thomas Edward James Edwards ◽  
Johann Michler ◽  
...  

1999 ◽  
Vol 39 (7) ◽  
pp. 91-98 ◽  
Author(s):  
Ryan N. Jordan ◽  
Eric P. Nichols ◽  
Alfred B. Cunningham

Bioavailability is herein defined as the accessibility of a substrate by a microorganism. Further, bioavailability is governed by (1) the substrate concentration that the cell membrane “sees,” (i.e., the “directly bioavailable” pool) as well as (2) the rate of mass transfer from potentially bioavailable (e.g., nonaqueous) phases to the directly bioavailable (e.g., aqueous) phase. Mechanisms by which sorbed (bio)surfactants influence these two processes are discussed. We propose the hypothesis that the sorption of (bio)surfactants at the solid-liquid interface is partially responsible for the increased bioavailability of surface-bound nutrients, and offer this as a basis for suggesting the development of engineered in-situ bioremediation technologies that take advantage of low (bio)surfactant concentrations. In addition, other industrial systems where bioavailability phenomena should be considered are addressed.


2020 ◽  
Vol 16 (4) ◽  
pp. 455-461
Author(s):  
Gabriela M. Baia ◽  
Otniel Freitas-Silva ◽  
Murillo F. Junior

Fruits and vegetables are foods that come into contact with various types of microorganisms from planting to their consumption. A lack or poor sanitation of these products after harvest can cause high losses due to deterioration and/ or pathogenic microorganisms. There are practically no post-harvest fungicides or bactericides with a broad spectrum of action that have no toxic residual effects and are safe. However, to minimize such problems, the use of sanitizers is an efficient device against these microorganisms. Chlorine is the most prevalent sanitizing agent because of its broad spectrum, low cost and well-established practices. However, the inevitable formation of disinfection by-products, such as trihalomethanes (THMs) and haloacetic acids (HAAs), is considered one of the main threats to food safety. Alternative sanitizers, such as chlorine dioxide (ClO2) and ozone, are becoming popular as a substitute for traditional post-harvest treatments. Thus, this review addresses the use of chlorine, chlorine dioxide and ozone emphasizing aspects, such as usage, safe application, spectrum of action and legislation. In order to ensure the quality and safety of final products, the adoption of well-prepared sanitation and sanitation programs for post-harvest fruits and vegetables is essential.


2019 ◽  
Author(s):  
Nikki Theofanopoulou ◽  
Katherine Isbister ◽  
Julian Edbrooke-Childs ◽  
Petr Slovák

BACKGROUND A common challenge within psychiatry and prevention science more broadly is the lack of effective, engaging, and scale-able mechanisms to deliver psycho-social interventions for children, especially beyond in-person therapeutic or school-based contexts. Although digital technology has the potential to address these issues, existing research on technology-enabled interventions for families remains limited. OBJECTIVE The aim of this pilot study was to examine the feasibility of in-situ deployments of a low-cost, bespoke prototype, which has been designed to support children’s in-the-moment emotion regulation efforts. This prototype instantiates a novel intervention model that aims to address the existing limitations by delivering the intervention through an interactive object (a ‘smart toy’) sent home with the child, without any prior training necessary for either the child or their carer. This pilot study examined (i) engagement and acceptability of the device in the homes during 1 week deployments; and (ii) qualitative indicators of emotion regulation effects, as reported by parents and children. METHODS In this qualitative study, ten families (altogether 11 children aged 6-10 years) were recruited from three under-privileged communities in the UK. The RA visited participants in their homes to give children the ‘smart toy’ and conduct a semi-structured interview with at least one parent from each family. Children were given the prototype, a discovery book, and a simple digital camera to keep at home for 7-8 days, after which we interviewed each child and their parent about their experience. Thematic analysis guided the identification and organisation of common themes and patterns across the dataset. In addition, the prototypes automatically logged every interaction with the toy throughout the week-long deployments. RESULTS Across all 10 families, parents and children reported that the ‘smart toy’ was incorporated into children’s emotion regulation practices and engaged with naturally in moments children wanted to relax or calm down. Data suggests that children interacted with the toy throughout the duration of the deployment, found the experience enjoyable, and all requested to keep the toy longer. Child emotional connection to the toy—caring for its ‘well-being’—appears to have driven this strong engagement. Parents reported satisfaction with and acceptability of the toy. CONCLUSIONS This is the first known study investigation of the use of object-enabled intervention delivery to support emotion regulation in-situ. The strong engagement and qualitative indications of effects are promising – children were able to use the prototype without any training and incorporated it into their emotion regulation practices during daily challenges. Future work is needed to extend this indicative data with efficacy studies examining the psychological efficacy of the proposed intervention. More broadly, our findings suggest the potential of a technology-enabled shift in how prevention interventions are designed and delivered: empowering children and parents through ‘child-led, situated interventions’, where participants learn through actionable support directly within family life, as opposed to didactic in-person workshops and a subsequent skills application.


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