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Flexible porous frameworks are at the forefront of materials research. A unique feature is their ability to open and close their pores in an adaptive manner induced by chemical and physical stimuli. Such enzyme‐like selective recognition offers a wide range of functions ranging from gas storage and separation to sensing, actuation, mechanical energy storage and catalysis. However, the factors affecting switchability are poorly understood. In particular, the role of building blocks, as well as secondary factors (crystal size, defects, cooperativity) and the role of host–guest interactions, profit from systematic investigations of an idealized model by advanced analytical techniques and simulations. The review describes an integrated approach targeting the deliberate design of pillared layer metal–organic frameworks as idealized model materials for the analysis of critical factors affecting framework dynamics and summarizes the resulting progress in their understanding and application. [ABSTRACT FROM AUTHOR]

The title compound, [Cr2(C2H3O2)4(C4H8O)2] or [Cr2(OAc)4(THF)2] (OAc is acetate, THF is tetrahydrofuran), was obtained by recrystallization of anhydrous chromium(II) acetate [Cr2(OAc)4] from hot tetrahydrofuran. The centrosymmetric complex forms monoclinic crystals, space group C2/c, and consists of two CrII atoms bridged by four acetate ligands. Additionally, each CrII atom is coordinated by a terminal THF ligand, which leads to a square-pyramidal coordination.

[Display omitted] We have synthesized two novel complexes of copper(ii) trichloro acetate, Cu 2 (CCl 3 COO) 3 (OH)(H 2 O)4·H 2 O and Cu(CCl 3 COO) 2 (MeCN), and determined their crystal structures and thermal stability. While the complex with acetonitrile has a discrete binuclear paddle-wheel structure, typical of copper carboxylates, the aqua-hydroxo complex belongs to a novel unique chain–molecular type of basic copper complexes. [ABSTRACT FROM AUTHOR]

The natural convection resultant from the uniform circular rotation of the paddle wheel in a cross-shaped porous cavity filled by Al 2 O 3 - H 2 O was simulated by the ISPH method. A cross-shaped cavity's two vertical area is saturated with a homogeneous porous medium, whereas the entire horizontal area is saturated with a heterogeneous porous medium. The paddle wheel rotates with a uniform circular velocity around the cavity's center. The paddle wheel's entire integrated body has temperature T h . The temperature is set on the inside walls of a cross-shaped cavity T c . The present geometry can be used to analyze and comprehend the thermo-physical behaviors of electronic motors. Angular velocity is set to ω = 7.15 , and thus, the natural convection case is only evaluated due to the low speed of inner rotating shape. The simulation results are graphically represented for temperature distributions, velocity fields, and tabular representations for the average Nusselt number. The important parameter ranges are the Rayleigh number (10 3 ≤ Ra ≤ 10 6) , paddle wheel length (2.5 ≤ L P ≤ 14) , nanoparticles parameter (0 ≤ ϕ ≤ 0.05) , and Darcy parameter (10 - 3 ≤ Da ≤ 10 - 5) . The results show that increasing the length of the paddle wheel increases heat transfer and nanofluid movements within a cross-shaped cavity. In addition, increasing the Rayleigh number improves heat transfer and the nanofluid speed inside a cross-shaped cavity. When the Darcy parameter is reduced, the fluid flow is restricted to the rotating inner shape. The value of Nu ¯ powers as the length of the paddle wheel and ϕ are increasing. [ABSTRACT FROM AUTHOR]

One type of aeration device is a paddle wheel which is the most common aerator used for aquaculture ponds (Wyban et al. 1989; Moore & Whitis 1999; Laksitanonta et al., 2003). The aeration rate is influenced by the surface area of water and air contact, the difference of oxygen concentration, coating film coefficient and turbulence (Boyd 1998) The geometry, and speed of the spin mill affect aeration performance (Peterson & Walker 2002; Moulick et al., 2002). Aerator performance is an important factor in the selection and use of aerators as they relate to investment and operational costs, so that the development of aerator design and improved operating performance is still possible to do. The purpose of this research is to know the comparison of paddle wheel performance result of modified design versus paddle wheels manufacturer. The research was designed with 2 (two) different types of paddle wheel which is the treatment of 1 (one) paddle wheel from the modified of construction design with a power of 0.37 kwh-1 0.5 hp and the treatment of 2 (two) artificial paddle wheel from manufacturer with 0.78 kwh-1 1 hp. Statistical analysis use T-test. The results of research is modified Paddle wheel (Treatment 1) was increased of DO = 2.56 ppm; Coverage area = 418929,6 cm2; diameter bursts= 132.2 cm. Conventional paddle wheel performance (treatment 2) was increased of DO = 2.54 ppm; Coverage area = 41983,8 cm2; The diameter of the bursts is 130.2cm. The t test results (statistic) on all variables showed no significant different (p= 0.595). This means the performance of the modified paddle wheel with 0.37 KWh-1 0.5 hp one phase is the same as the conventional paddle wheel performance with 0.78KWh-1 1 hp two phase power but there are energy saving 0.41 KWh-1.

[Display omitted] • A new dinuclear Cu(II) based paddle wheel type complex is prepared. • Photoluminescence and photocatalytic properties have been examined for this complex. • Complex demonstrates good photocatalytic performance, achieving 78.26% degradation against methylene blue (MB). • The DFT calculations support the experimental findings. A paddle wheel-shaped complex formulated [Cu 2 (piv) 4 (CH 3 OH) 2 ]·1.5(CH 3 OH)·0.5(H 2 O) (1) has been synthesized by a reaction of Cu(NO 3) 2 ·3H 2 O with pivalic acid. The structure of the complex is characterized by FTIR, elemental analysis and single X-ray crystallography. The crystal structure demonstrates that complex exhibits a paddle wheel type configuration. The asymmetric unit of 1 is composed of a half molecule due to the existence of an inversion center between the two Cu(II) centers. The oxygen atoms of the pivalate serve as bridging ligands, and the two methanol molecules occupy the axial position. Each pivalate ion has syn-, syn - coordination mode and its geometry may be described as square pyramidal. The complex works well as a photocatalyst, breaking down methylene blue (MB) by 78.26% after 120 minutes of 30 W ultraviolet light exposure. The optimized photocatalytic parameters were as follows; catalyst loading = 40 mg, primary concentration of MB = 15 mg/L, temperature = 323K, and pH = 8. The reaction kinetics were best demonstrated by a pseudo-first-order kinetic model followed by a rate constant of 0.00715 min–1. The reuse of the catalyst over five photocatalytic runs suggested its excellent sustainability and recyclability. Hydroxyl radicals and superoxide anions were found to be active participants in the catalytic reaction, as investigated by scavenging studies. These findings contributed to a deeper understanding of the mechanistic aspects of the photocatalytic reaction. Theoretical investigation is well support to experimental work. [ABSTRACT FROM AUTHOR]

The filling level within feed frames and the uniformity of the powder supply by feed frames for die filling have not been monitored so far during tableting processes. This study was intended to investigate if the powder filling level inside a rotary tablet press feed frame is affected by the feed frames' paddle wheel speed and/or by the turret speed. Furthermore, it was examined whether the filling level affects the resulting tablet masses while filling the respective dies. Two tableting excipients one with poor flowability and one with excellent flowability were selected as model powders. For inline analysis within the feed frame, a laser triangulator was used, which at a particular position scans the powder surface level within the filling chamber of the feed frame and, combined with the recognition of the angle position of the paddle wheel by a rotary encoder, calculates the filling level and the uniformity of the powder supply by an in-house written software. Results show that the turret speed, the paddle wheel speed and the powder characteristics may all affect the filling level within the filling chamber. The presented method is suitable for inline monitoring of the filling level in the filling chamber of the feed frame and the homogeneity of the powder supply for die filling during tableting. Moreover, a decrease of the filling level during tableting and/or a sudden refill effect of the filling chamber can be detected as well, which may occur under certain process settings at the end of the tablet production and may influence the tablet mass. The results also showed that initial deviations of the filling levels of the individual paddle wheel interspaces persisted until the end of the tableting runs, which might be one of the reasons for tablet mass deviations during production. Unlabelled Image • Presented method is suitable for inline monitoring of filling level within feed frame. • Turret speed, paddle wheel speed, powder characteristics may affect the filling level. • A decrease of filling level during tableting and sudden refill effect were observed. • Persistence of initial filling level inhomogeneities between paddle wheel interspaces. [ABSTRACT FROM AUTHOR]

Abstract The present study deals with the synthesis of paddle-wheel structured binuclear Mn-TP complex via molecular adduct with chloride salt of Mn. We report a novel N,N,N′,N′- tetramethylbutane1,4-diammonium bis(4-amino benzoate) C 8 H 22 N 2 2+. 2C 7 H 6 NO 2 −. 2.25H 2 O (TP) and its binuclear metal–organic framework having a channel for hydrophilic guest molecules. Another interesting structural feature of ligand TP has the hexagonal cavity along with the stream of four waters molecules in the host hydrophilic channels. Both experimental and theoretical studies of bonding parameters, as well as optimized structure for Mn-TP complex were in good agreement with each other. Both Mn atoms lead to closed polyhedra with four PABA molecules and chlorine atoms. Graphical abstract Image [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to investigate whether the filling level within the feed frame of a rotary tablet press can be quantified by laser triangulation combined with the angle recognition of one paddle wheel via rotary encoder. Significance: Rotary tablet press feed frames are supposed to assure a uniform die filling and, thus, to guarantee the weight and content uniformity of the resulting tablets. Therefore, a constant bulk availability and flow within the feed frame is crucial and has to be ensured by the feed frame design and the operating conditions. So far, there is no instrument available to monitor the bulk filling level or the bulk distribution within feed frames. Methods: Calcium phosphate dihydrate was used as model powder. The powder surface level was determined via laser triangulation and the angle position of the paddle wheel was monitored via incremental rotary encoder. The data of both parameters was acquired synchronously and evaluated by in-house written software. Results: Different powder masses led to significantly different filling level signals. The experiments showed a high reproducibility of the determined filling levels. Furthermore, an influence of the rotational speed on the powder distribution was observed. Conclusions: The developed instrument may be used for quantification of the volumetric filling level within rotary tablet press feed frames. It may either be used to better understand the powder behavior within feed frames or for improvement of the die filling process by implementing the device into a feedback loop. [ABSTRACT FROM AUTHOR]

Turbulence mixing is critical for generating high microalgal biomass productivity. Mixing also represents a major operational cost in large-scale microalgal production. The integration of photovoltaic cells with microalgae cultivation systems has been shown to eliminate the requirement of conventional grid-supplied electricity in rural areas. However, through such systems, the availability of electricity and the operation of equipment would solely depend on available sunlight and limited to only daytime. In accordance, in this study, we evaluated the effect of continuous paddle wheel mixing (24 h) and daytime mixing (12 h) on the growth, productivity and photosynthesis of Nannochloropsis sp. grown in outdoor paddle wheel driven raceway ponds operated at different depths (15 and 25 cm). Specific growth rates, volumetric and aerial biomass productivities were found to be significantly higher in ponds with 24 hour mixing compared to ponds with only 12 hour mixing operated at the same depth. The depth of the cultures did not affect the growth rate and volumetric productivity of cultures in both mixing conditions. Photosynthetic performance of cultures evaluated through chlorophyll a fluorescence measurements of photosystem II trended higher in ponds with 24 hour mixing compared to ponds subjected to 12 hour mixing. Our results clearly indicate the importance of continuous mixing to achieve high biomass productivity in cultures of Nannochloropsis sp. [ABSTRACT FROM AUTHOR]

Abstract: The crystalline phase β‐[N(CH3)4]2HP3O9 undergoes a reversible phase transition to γ‐[N(CH3)4]2HP3O9, which was studied by dynamic scanning calorimetry and X‐ray diffraction. The rotational dynamics of the anion [P3O9]3− were evident from variable temperature 31P magic angle spinning (MAS) NMR spectroscopy. The rotational dynamics could be simulated with a 3‐site jump model, which yields spectra in good agreement with experiment. An activation energy of 0.6 eV could be estimated from line shape analysis. Impedance spectra reflect a bulk proton conductivity of γ‐[N(CH3)4]2HP3O9 of 6.9×10−5 S cm−1 at 240 °C and an activation energy of approximately 1.0 eV. Thus this salt features bulk protonic motion, while local rotational anionic motion happens with activation energies of the same order, as suggested by the paddle‐wheel mechanism. [ABSTRACT FROM AUTHOR]

The title compound, [Cr 2 (C 2 H 3 O 2 ) 4 (C 4 H 8 O) 2 ] or [Cr 2 (OAc) 4 (THF) 2 ] (OAc is acetate, THF is tetra-hydro-furan), was obtained by recrystallization of anhydrous chromium(II) acetate [Cr 2 (OAc) 4 ] from hot tetra-hydro-furan. The centrosymmetric complex forms monoclinic crystals, space group C 2/ c , and consists of two Cr II atoms bridged by four acetate ligands. Additionally, each Cr II atom is coordinated by a terminal THF ligand, which leads to a square-pyramidal coordination., (© Heiser and Merzweiler 2023.)