Preparation and Characterization of Calcium Cross-Linked Starch Monolithic Cryogels and Their Application as Cost-Effective Green Filters

Monolithic cryogels from starch were successfully synthesized and applied as alternative biodegradable filters for the first time. Rice flour was cross-linked with Ca2+ from limewater during gelatinization before being frozen and then thawed for three cycles. The resultant material was then soaked in ethanol for 3 h before incubation at 80 °C for 1 h, yielding monolithic material with interconnected pores in sizes of 51 ± 18 to 52 ± 15 µm without any need of freeze-drying. The cryogels possessed macroporous structure with specific surface areas from 1.1 to 4.3 m2g−1, they could adsorb water from 599 ± 27 to 635 ± 59% of their dry weight with low swelling ratios of 6.0 ± 0.3 to 6.4 ± 0.6 gwater/gcryogel, and could be applied as biofilters to remove suspended particles and reduce the light absorption of water sample from 25 ± 3 to 96 ± 5%. The prepared biofilters can be re-used up to three times, although they cost only USD 0.0004/piece. Complete weight loss resulted from burial in soil for 30 days, indicating environmentally friendly biodegradation and potential for environmental applications.

An embezzler test for norms, standards and regulations

Purpose The purpose of this study is to address the question that economic standards, norms and regulations can possess weak spots that might be exploitable for the embezzlement of an organization’s assets with resultant material consequences in money laundering,tax evasion, fraud, corruption and other potential financial crimes. Design/methodology/approach The author’s methodological approach is to introduce and discuss a new logical-deductive test that the author names “embezzler test”. The author’s test investigates regulatory architectures from the perspective of someone attempting to divert assets from or to an organization. It appraises whether a potential embezzler could divert resources without being detected and sanctioned. Findings The embezzler test can be applied to a broad range of standards, norms and regulations. Research limitations/implications This new test can be improved and further calibrated in future research. Practical implications Researchers, regulators and law makers can use the new test to identify and eventually fix weak spots for embezzlement in norms, standards and regulations. Originality/value To the best of the author’s knowledge, such a test has never been formulated or applied before to identify weak spots for potential embezzlement in regulatory architectures.

ZnCDs/ZnO@ZIF-8 Zeolite Composites for the Photocatalytic Degradation of Tetracycline

Considering the photocatalytic performance of CDs, ZnO, and the unique porous nanostructure and stability of ZIF-8, we prepared ZnCDs/ZnO@ZIF-8 zeolite composites. The resultant material represented an enhanced ability for the photodegradation of TC compared with that of ZnCDs and ZnO. The photocatalytic degradation efficiency reached over 85%. The catalytic activity of the composites was maintained after four cycles. The experimental result indicated that ×O2 radical was the active species in the reaction.

Effect of Al3+ Substitution On Magnetic and DC Electrical Resistivity Properties of NiZnCu Nanoferrites

Al substituted Ni0.4Zn0.35Cu0.25Fe2-xAlxO4 (x = 0.00, 0.05, 0.10, 0.15, 0.20) samples is synthesized using the sol-gel auto-combustion process. X-ray diffraction shows its cubic spinel structure. The lattice constant decreases as the Al3+ content increases. The sizes of the crystallites are also decreasing in the range of 32.15 nm to 22.89 nm. The wavenumbers of tetrahedral and octahedral sites sighted in the FT-IR spectra are similar to that of the precursor. The increment in the Al3+ content increases the DC conductivity. The electrical resistivity decrease with an increase in the temperature, i.e., it has a negative temperature coefficient with resistance similar to semiconductors. VSM results show their isotropic nature forming single domain ferrimagnetic particles. The resultant material is widely significant, as indicated by its result.

Clinching of Thermoplastic Composites and Metals—A Comparison of Three Novel Joining Technologies

Clinching continuous fibre reinforced thermoplastic composites and metals is challenging due to the low ductility of the composite material. Therefore, a number of novel clinching technologies has been developed specifically for these material combinations. A systematic overview of these advanced clinching methods is given in the present paper. With a focus on process design, three selected clinching methods suitable for different joining tasks are described in detail. The clinching processes including equipment and tools, observed process phenomena and the resultant material structure are compared. Process phenomena during joining are explained in general and compared using computed tomography and micrograph images for each process. In addition the load bearing behaviour and the corresponding failure mechanisms are investigated by means of single-lap shear tests. Finally, the new joining technologies are discussed regarding application relevant criteria.

Effect of Cu Substitution on Magnetic and DC Electrical Resistivity Properties of Ni-Zn Nano Ferrites

Cu substituted Ni0.5Zn0.5-xCuxFe2O4 (x = 0, 0.1, 0.2, 0.3 and 0.4) samples is synthesized using the sol-gel auto-combustion process. X-ray diffraction shows its cubic spinel structure. The lattice constant decreases as the Cu content increases. The sizes of the crystallites are also decreasing in the range of 42.68 nm to 21.75 nm. The wavenumbers of tetrahedral and octahedral sites sighted in the FTIR spectra are similar to that of the precursor. The increment in the copper content increases the DC conductivity. The electrical resistivity decrease with increase in the temperature, i.e. it has a negative temperature coefficient with resistance similar to semiconductors. The remnant ratios R obtained from VSM show their isotropic nature forming single domain ferrimagnetic particles. The resultant material is widely significant, as indicated by its result.

DC Electrical Resistivity and Magnetic Properties of Co Substituted NiCuZn Nano Ferrite

Co substituted Ni0.3-xCoxCu25Zn0.45Fe2O4 (x = 0, 0.05, 0.1, 0.15 and 0.2) samples is synthesized using the sol-gel auto-combustion process. X-ray diffraction shows its cubic spinel structure. The lattice constant decreases as the Co content increases. The sizes of the crystallites are in the range of 20.18–26.24 nm. The wavenumbers of tetrahedral and octahedral sites sighted in the FTIR spectra are similar to that of the precursor. The increment on the Co content increases the DC conductivity. The electrical resistivity decrease with increase in the temperature, i.e. it has a negative temperature coefficient with resistance similar to semiconductors. The remnant ratios R obtained from VSM show their isotropic nature forming single domain ferrimagnetic particles. The resultant material is widely significant, as indicated by its result.

Oenothera Biennis Extract as Reducing Agent for the Synthesis of Pd NPs Supported on Halloysite Functionalized With Schiff Base: an Efficient Catalyst for Cu- and Ligand-free Sonogashira Reaction in Aqueous Media

A hybrid system was designed and synthesized through reacting modified halloysite (Hal-Cl) with Schiff base (DAB-PC) and applied as catalytic support for anchoring Pd NPs to afford Pd@Hal-DAB-PC catalyst. The resultant material was well identified by various analyses including FT-IR, XRD, TGA, FE-SEM, and EDS, and revealed outstanding catalytic activity in the Sonogashira reaction in aqueous media. Also, This nanocatalyst was simply collected and recycled up to six runs with a slight drop of the efficiency, indicating the durability of Pd@Hal-DAB-PC.

On Catalytic Behavior of Bulk Mo2C in the Hydrodenitrogenation of Indole over a Wide Range of Conversion Thereof

The catalytic activity of bulk molybdenum carbide (Mo2C) in the hydrodenitrogenation (HDN) of indole was studied. The catalyst was synthesized using a temperature-programmed reaction of the respective oxide precursor (MoO3) with the carburizing gas mixture of 10 vol.\% CH4/H2. The resultant material was characterized using X-ray diffraction, CO chemisorption, and nitrogen adsorption. The catalytic activity was studied in the HDN of indole over a wide range of conversion thereof and in the presence of a low amount of sulfur (50 ppm), which was used to simulate the processing of real petroleum intermediates. The molybdenum carbide has shown high activity under the tested operating conditions. Apparently, the bulk molybdenum carbide turned out to be selective towards the formation of aromatic products such as ethylbenzene, toluene, and benzene. The main products of HDN were ethylbenzene and ethylcyclohexane. After 99% conversion of indole HDN was reached (i.e., lack of N-containing compounds in the products was observed), the hydrogenation of ethylbenzene to ethylcyclohexane took place. Thus, the catalytic behavior of bulk molybdenum carbide for the HDN of indole is completely different compared to previously studied sulfide-based systems.