Reconfigurable Disk-like Microswarm under a Sawtooth Magnetic Field

Swarming robotic systems, which stem from insect swarms in nature, exhibit a high level of environmental adaptability and enhanced tasking capabilities for targeted delivery and micromanipulation. Here, we present a strategy that reconfigures paramagnetic nanoparticles into microswarms energized by a sawtooth magnetic field. A rotary-stepping magnetic-chain mechanism is proposed to address the forming principle of disk-like swarms. Based on programming the sawtooth field, the microswarm can perform reversible transformations between a disk, an ellipse and a ribbon, as well as splitting and merging. In addition, the swarms can be steered in any direction with excellent maneuverability and a high level of pattern stability. Under accurate manipulation of a magnetic microswarm, multiple microparts with complicated shapes were successfully combined into a complete assembly. This reconfigurable swarming microrobot may shed light on the understanding of complex morphological transformations in living systems and provide future practical applications of microfabrication and micromanipulation.

Aerobic Oxidative Desulfurization of Liquid Fuel Catalyzed by P–Mo–V Heteropoly Acids in the Presence of Aldehyde

Aerobic oxidative desulfurization (ODS) of model liquid fuel (dodecane spiked with dibenzothiophene (DBT)) was carried out in the presence of bulk and supported Keggin-type heteropoly acids H3+nPMo12-nVnO40 (HPA-n, n = 0–3) as heterogeneous catalysts and benzaldehyde as a sacrificial reductant. In the presence of bulk H4PMo11VO40 (HPA-1), 100% of DBT was removed from fuel (converted to DBT sulfone) at 60 °C and ambient air pressure. Multiple catalyst reuse without loss of activity was demonstrated. The ODS reaction was strongly inhibited by radical scavengers. An unbranched radical chain mechanism was proposed.

Functional Morphology of the Flight Apparatus of Ephemera vulgata (Ephemeroptera: Ephemeridae) and Implications for the Evolution of Flight in Insects

The mesothoracic flight apparatus of preserved and freshly killed specimens of Ephemera vulgata is examined in detail by means of functional morphological examinations. The basic drive mechanism of the forewing of Ephemera vulgata constitutes a four-bar kinematic chain, which encompasses the whole mesothorax. Based on this reassessment, the operating principles of the different subsystems of the flight apparatus of the mayfly were newly analysed. As in the Neoptera, the indirect dorsolongitudinal downstroke and dorsoventral upstroke muscles rotate the wing around an axis which runs through the main wing joint of the fulcrum. In contrast to the Neoptera, the wing is driven via the posterior notal wing process and fourth axillary. A strong direct subalar muscle is able to move the subalare (together with the pleural ridge) inwards and to affect the wingstroke via a bistable click mechanism in this unusual way. The axillary sclerites, two frontal first axillaries and one caudal fourth axillary, permit the radioanal plate to rotate forward–backward on the fulcrum. This motion system, which is superimposed on the kinematic chain mechanism, permits alterations of the wingstroke plane. A short muscle of the radioanal plate allows adjusting the passive pronation of the wing during the downstroke and achieving an increase of the aerodynamical angle of attack. The step-by-step derivability of basal flight mechanisms of the main groups of Pterygota indicates a paranotal origin of the wings. The possibility that the Ephemeroptera and Neoptera constitute sister groups is discussed.

ANALISIS RANTAI PASOK KOMODITI CABAI RAWIT DI PASAR BERSEHATI KOTA MANADO DI MASA PANDEMI COVID-19

This study aims to analysis the supply chain mechanism for the cayenne pepper commodity in the Bersehati Market of Manado City during the Covid-19 pandemic. The data used in this study are primary data and secondary data. Primary data were obtained from observations, direct interviews, and interviews via WhatsApp with traders, consumers, and service providers in the Bersehati market. Secondary data were collected and obtained from employees in the Bersehati Market. The sampling method was carried out using the purposive sampling method (deliberately), namely selecting sources of information in the Bersehati Market. Number of sample used in this study was taken 10 respondents divided into 5 retailers, 3 consumers, 1 service provider, 1 market officer. This study uses descriptive analysis which is an analytical method used to determine the supply chain mechanism of cayenne pepper. The results showed that the supply chain mechanism for the cayenne pepper commodity in the Bersehati Market during the Covid-19 pandemic was related to product flows, financial flows and information flows that had differences in each flow. During the pandemic, there were 6 links that played an active role in the supply chain for the chili commodity at the Bersehati Market.

Degradation of Bisphenol A in an Aqueous Solution by a Photo-Fenton-Like Process Using a UV KrCl Excilamp

Bisphenol A (BPA), a precursor to important plastics, is regarded as a common aquatic micropollutant with endocrine-disrupting activity. In the present study, we explored the capability of a UV KrCl excilamp (222 nm) to degrade BPA by a photo-Fenton-like process using persulfate under flow-through conditions. The first-order rate constants of degradation were obtained and the mineralization of dissolved organic carbon (DOC) was estimated. The results showed complete BPA degradation and high DOC mineralization (70–97%). A comparative analysis of degradation rates and DOC removal in the examined systems (UV, Fe2+/S2O82−, UV/S2O82− and UV/Fe2+/S2O82−) revealed a significant synergistic effect in the photo-Fenton-like system (UV/Fe2+/S2O82−) without the accumulation of toxic intermediates. This indicated that the BPA was oxidized via the conjugated radical chain mechanism, which was based on the photo-induced and catalytic processes involving HO• and SO4−• radicals. The primary intermediates of BPA degradation in the UV/Fe2+/S2O82− system were identified by HPLC/MS and the oxidation pathway was proposed. The high performance of the photo-Fenton-like process employing a quasi-monochromatic UV radiation of a KrCl excilamp offers promising potential for an efficient removal of such micropollutants from aqueous media.

Theoretical investigation of the side-chain mechanism of the MTO process over H-SSZ-13 using DFT and ab initio calculations

The side-chain mechanism of the methanol-to-olefins process over the H-SSZ-13 acidic zeolite was investigated using periodic density functional theory with corrections from highly accurate ab intio calculations on large cluster models.

Classification of schemes of volumetric hydraulic machines according to the types of plain kinematic chains limiting their working chambers

A classification of volumetric hydraulic machines is proposed, which is based on the structure of a plain kinematic chain that closes the working chamber. The class of the hydraulic machine determines the number of bodies included in this chain; the series determines composition of the kinematic pairs of this chain. The classification covers all volumetric hydraulic machines used in modern technology. Keywords: volumetric hydraulic machine, classification, working chamber, kinematic chain, mechanism structure. [email protected]