Abstract: Metal nanoparticle-deposited, nitrogen-doped carbon adsorbents are disclosed, along with methods of removing sulfur compounds from a hydrocarbon feed stream using these adsorbents.

Abstract: A Mg-doped alumina aerogel and a manufacturing method thereof are provided. The Mg-doped alumina aerogel is a three-dimensional cross-linked network structure including a plurality of magnesium atoms, a plurality of aluminum atoms, a plurality of oxygen atoms, and a plurality of hydrogen atoms. The three-dimensional cross-linked network structure has a —Mg—O—Al— bond at least on the main chain.

Abstract: The present invention provides a method for producing an oxide catalyst containing antimony, comprising a step (A) of obtaining the oxide catalyst using antimony particles containing a diantimony trioxide as a source of the antimony, wherein an abundance of a pentavalent antimony in a surface layer of the antimony particle to be measured in XPS analysis is less than 70 atom %, and the antimony particle has an average particle size of 1.2 ?m or less.

Abstract: A catalyst system for the conversion of glycerin to allyl alcohol, the catalyst system comprising: a rhenium compound selected from rhenium dioxide, rhenium trioxide, and a combination thereof. A method of producing allyl alcohol from glycerin via the catalyst system, the method comprising exposing glycerin to a temperature of greater than 140° C. in the presence of a catalyst comprising rhenium trioxide, rhenium dioxide, or a combination thereof to produce a product comprising allyl alcohol.

Abstract: The present application relates to a Fischer-Tropsch catalyst body having an open-celled foam structure, said catalyst body comprising a substrate material and a catalytic active material or precursor thereof wherein: —The substrate material: ?is a metal alloy or ceramic material; ?having a surface roughness of 50 ?m or more; ?has an open-celled foam structure with at least 15 pores per inch; and —The catalytically active material or precursor thereof which: ?is present on the surface of the substrate material; ?comprises cobalt, iron, ruthenium or a combination thereof; and ?comprises a catalyst support selected from titania, alumina or silica.

Abstract: A monolithic catalyst used for a carbon dioxide hydrogenation reaction and a method for preparing the same. The catalyst comprises a carrier, a coating, and active components. The carrier is a honeycomb ceramic. The coating and the active components are separately applied to honeycomb ceramic hole walls from inside to outside. Moreover, each of the honeycomb ceramic holes is divided into an upper segment and a lower segment, and different active components are separately loaded on the two segments. The method for preparing the monolithic catalyst comprises first applying a coating to a honeycomb ceramic by means of impregnation to obtain a coating-containing carrier, and then applying active components to an upper segment and a lower segment of the coating-containing carrier successively by means of impregnation to obtain the monolithic catalyst.

Abstract: A variety of redox catalysts, methods of making, and methods of using thereof are provided. Surface modified redox catalysts are provided having an oxygen carrier core with an outer surface that has been modified to enhance the selectivity of the redox catalyst for oxidative dehydrogenation. The surface modification can include forming a redox catalyst outer layer on the outer surface and/or suppressing sites that form nonselective electrophilic oxygen sites on the outer surface of the oxygen carrier. A variety of methods are provided for making the surface modified redox catalysts, e.g. modified Pechini methods. A variety of methods are provided for using the catalysts for oxidative cracking of light paraffins. Methods are provided for oxidative cracking of light paraffins by contacting the paraffin with a core-shell redox catalyst described herein to convert the paraffins to water and olefins, diolefins, or a combination thereof.

Abstract: A hydrogenation reaction catalyst used for a reaction of 1,4-anhydroerythritol and hydrogen to produce 3-hydroxytetrahydrofuran includes a carrier, at least one oxide selected from the group consisting of an oxide of a Group 6 element and an oxide of a Group 7 element, the oxide being supported on the carrier, and a metal other than a Group 6 element and a Group 7 element, the other metal being supported on the carrier. The amount of the oxide supported on the carrier in terms of a metal atom forming the oxide is 0.01 to 10% by weight based on the total amount of the oxide and the carrier being 100% by weight. The molar ratio in terms of metal of the other metal to the Group 6 element and Group 7 element forming the oxide [other metal/Group 6 element and Group 7 element] is 50/1 to 1/4.

Abstract: The present invention clarifies the characteristic of the hygroscopicity of the catalyst for producing acrylic acid and finds out a relationship between the water amount of the catalyst and the catalytic performance as the catalyst for producing acrylic acid, and provides an excellent catalyst. Provided is a catalyst for producing acrylic acid, which contains molybdenum and vanadium as essential active components, in which the amount of water contained in the catalyst is 0.01 mass % or more and 0.53 mass % or less.

Abstract: The present invention relates to a catalyst system comprising a transition metal compound on a solid carrier which is a surface-reacted calcium carbonate. The invention further relates to a method for manufacturing said catalyst system and to its use in heterogeneous catalysis.

Abstract: A process for producing a metal carbonate-containing shaped catalyst body for the hydrogenation of an organic compound having one or more carbonyl group, in which a) a metal carbonate composition which contains, based on the total weight of the metal carbonate composition, from 70 to 94.5% by weight of a metal carbonate mixture containing two or more than two metal carbonates of two or more than two different metals (M), from 5 to 25% by weight of metallic copper, and from 0.5 to 5% by weight of tableting aid is provided, b) a shaped body is formed from the metal carbonate composition provided in step a), and c) the shaped body obtained in step b) is activated in the presence of hydrogen at a temperature in the range from 150 to 250° C.

Abstract: An oxidation catalyst composite, methods, and systems for the treatment of exhaust gas emissions from a diesel engine are described. More particularly, an oxidation catalyst composite including a first washcoat layer comprising a Pt component and a Pd component, and a second washcoat layer including a refractory metal oxide support containing manganese, a zeolite, and a platinum component is described.

Abstract: A hydroconversion catalyst obtained by the process described, comprising a mesoporized zeolite with healed zeolitic structure, containing at least one network of micropores and at least one network of mesopores, having an atomic Si/Al ratio within the zeolite framework of greater than or equal to 2.3 and showing reduced amount of extra-framework aluminium with regard to that of a mesoporized zeolite with no healed zeolitic structure.

Abstract: A catalyst for synthesizing aromatic hydrocarbons, a preparation method thereof and a method for synthesizing aromatic hydrocarbons by using the catalyst. The catalyst comprises acidic molecular sieve particles and zinc-aluminum composite oxide particles. The catalyst has relatively high selectivity to aromatic hydrocarbons, particularly BTX, stable performance, and a long single-pass life.

Abstract: The present invention relates to a process for preparing a catalyst for alkane aromatization providing high % conversion, high yield, high selectivity of aromatics, and high selectivity of p-xylene in xylene, wherein said process comprises the following steps: (a) contacting a zeolite with a solution of group IIIA metal salt; (b) contacting the zeolite obtained from step (a) with the solution of metal salt selected from a group VIIB metal, a group VB metal, or a mixture thereof; and (c) contacting the zeolite obtained from step (b) with alkoxysilane, characterized in that the solution of salt in step (b) comprising a glycol solvent as a reducing agent under a basic condition, and step (b) is operated at the temperature higher than 120° C.

Abstract: Catalysts are disclosed having metal oxide support structures and acidic reaction sites. Those reaction sites may have multiple bromine atoms bound to an aluminum atom with that aluminum-bromine group having an associated hydrogen ion. Additional structural features of the reaction sites are dictated by the aluminum oxide based catalysts and a silicon oxide based catalyst selected.

Abstract: This application consists of a method for the synthesis of a type of FER/MOR composite molecular sieve. That method consisting of mixing FER seed crystals, MOR seed crystals, a silicon source, water and an acid or alkali, thus yielding a reaction mixture; by adjusting the proportions of the seed crystals added, the silicon-aluminium proportion, acidity/alkalinity and other reaction conditions, it is possible to obtain a dual phase composite molecular sieve within which the proportions of the crystal phases may be adjusted. In the synthesis process to which the method of this application relates, there is no need to add any organic template, thus reducing the cost of the reaction, in addition to reducing likely environmental pollution, thus having major potential applications.

Abstract: The present invention provides an exhaust gas purifying composition containing BEA zeolite containing phosphorus, wherein an amount of phosphorus is such that a molar ratio thereof with respect to Al in the zeolite is 0.5 or greater, and a maintaining factor RS of a specific surface area of the exhaust gas purifying composition after heating at 980° C. for 25 hours is 35% or greater. Furthermore, the present invention also provides an exhaust gas purifying composition containing phosphorus-containing zeolite, wherein an amount of phosphorus is such that a molar ratio thereof with respect to Al in the zeolite is from 0.5 to 8, and a maintaining factor Rd of a crystallite diameter after heating at 980° C. for 25 hours is 50% or greater. The exhaust gas purifying composition of the present invention has excellent HC purifiability for exhaust gas purification in internal combustion engines such as gasoline engines.

Abstract: The present invention relates to a method of preparing an aromatic compound from acetylene, which includes synthesizing an aromatic compound from an acetylene-containing reactant gas in the presence of a zeolite catalyst for the aromatization of acetylene, and subjecting the zeolite catalyst deactivated by the coke formed in the aromatization of acetylene, to plasma treatment at ambient temperature and pressure so as to selectively remove the external cokes and partial internal coke, thereby regenerating the zeolite catalyst; a method of regenerating the zeolite catalyst used in the aromatization of acetylene by plasma treatment; and a regenerated zeolite catalyst for the aromatization of acetylene, prepared thereof.

Abstract: Precatalysts and catalytic processes for the functionalization of sp2-carbons using the precatalysts are described herein. The precatalysts comprise an intramolecular Frustrated Lewis Pair (FLP) that is generated in situ from the corresponding precatalyst fluoroborate salts. The precatalyst fluoroborate salts are deprotected in situ to generate catalysts including intramolecular FLPs for the dehydrogenative borylation of alkenes, arenes and heteroarenes. The catalytic process comprises contacting a precatalyst, a functionalization reagent; and a substrate comprising a sp2-H carbon, under conditions to provide a substrate comprising a functionalized sp2 carbon.

Abstract: The present invention relates to a self assembled catalyst. More particularly, the present invention relates to a self-assembled catalyst of formula (I) comprising supramolecular phosphine and carboxylate ligands, process for preparation thereof and use of said catalyst of formula (I) in olefin polymerization.

Abstract: Catalyst compositions for the conversion of aldehyde compounds and primary alcohol compounds to olefins are disclosed herein. Reactions include oxidative dehydroxymethylation processes and oxidative dehydroformylation methods, which are beneficially conducted in the presence of a sacrificial acceptor of H2 gas, such as N,N-dimethylacrylamide.

Abstract: A honeycomb structure, including: a pillar-shaped honeycomb structure body having a first end face and a second end face and including a porous partition wall disposed so as to surround a plurality of cells, the plurality of cells extending from the first end face to the second end face and serving as a through channel of fluid, wherein the partition wall has a porosity of 45 to 65%, the partition wall has an average pore diameter of 15 to 25 ?m, and the partition wall has a cumulative pore volume, which is measured by mercury intrusion porosimetry, such that a pore volume ratio of pores having pore diameters of 10 ?m or less relative to the overall pore volume of the partition wall is 10% or less, and a pore volume ratio of pores having pore diameters of 40 ?m or more is 10% or less.

Abstract: The present invention relates to preparation of catalyst for production of olefinic hydrocarbons by dehydrogenation of their corresponding paraffins, particularly propylene from propane, comprising a metal oxide or combination of metal oxides utilizing spent catalyst from Fluid Catalytic Cracking (FCC)/Resid Fluid Catalytic Cracking (RFCC) processes. The metal oxides are possibly from transition metal group, particularly from groups VB, VIB, VIII, and Lanthanide series, and at least one metal from alkali group. The catalyst support used is spent catalyst or modified spent catalyst or combination thereof. The said catalyst can be used for both non-oxidative Propane Dehydrogenation (PDH) and Oxidative Propane Dehydrogenation (OPDH) process in the presence of CO2.

Abstract: In order to facilitate disassembly of the fluid dispensing unit (4), the latter has the covering cap (17) with which at least one sealing means (18) located in the head part (12) of the fluid dispensing unit (4) can be fixed in its use position. In order to release the covering cap (17) from the head part (12), said covering cap is rotatable relative to the head part (12). A releasable snap connection (19) is provided between the covering cap (17) and the head part (12), said snap connection being formed by at least one latching projection (20) and/or at least one latching depression (21), wherein at least one oblique surface (22) is formed on the latching projection (20) and/or on the latching depression (21), said surface being oriented in such a manner that the snap connection (19) can be released by rotation of the covering cap (17) relative to the head part (12) (FIG. 3).

Abstract: A sterile container for processing in a closed circuit a mixture separable into layers, comprises a chamber for containing a mixture separable into layers, a first connector for coupling to an injection device and/or a removing device, the latter for removal of a layer of a multi-layer mixture. connector enables a fluid connection between the chamber and the injection device and/or the removing device. A first conduit, inside the chamber, is dimensioned to enable removal of the first layer. The container includes a second connector for coupling with the injection device and enabling fluid connection between the chamber and the injection device. The second connector is conformed for coupling also to the removing device. A second conduit inside the chamber is dimensioned to enable removal of a second layer of the multi-layer mixture.

Abstract: Fluid sample conduits have absorbing bodies to absorb contaminants in fluid samples or suspensions. The absorbing bodies are shaped to provide surface area for absorption, absorbent materials, and have flow channels for decontaminated portions of the sample to flow through the couduit and be collected. Applications include those in the medical and industrial fields. Absorbing bodies according to this disclosure can also serve the functions of discarding, changing, analyzing, and signaling the composition or physical characteristic or contents of the first, contaminated portion of a fluid sample or suspension through a conduit assembly.

Abstract: A material for manipulating liquid includes a porous substrate having first and second surfaces; and a wedge-shaped transport element disposed on one of the first and second surfaces, wherein the wedge-shaped transport element has a narrow end and a wide end, the wide end connected to a first reservoir, wherein the wedge-shaped transport element is configured to pass liquid from the narrow end to the wide end to the first reservoir, regardless of gravity, and wherein the first reservoir is configured to pass liquid away from the substrate in a z-direction opposite from the surface on which a liquid is deposited. The surface on which the wedge-shaped transport element is disposed is one of hydrophobic or superhydrophobic, and the wedge-shaped transport element is one of a) superhydrophilic when the first surface is hydrophobic, b) superhydrophilic when the first surface is superhydrophobic, and c) hydrophilic when the first surface is superhydrophobic.

Abstract: A reaction vessel holder (120) receives a reaction vessel (110). The reaction vessel (110) has a portion that is substantially optically transparent to light of a first range of wavelengths. The reaction vessel holder (120) comprises a body having a high thermal conductivity that is thermally coupled to and supports the reaction vessel (120). The body is further thermally coupled to a thermal device (130) for heating or cooling the reaction vessel holder (120) and thereby the reaction vessel (110). The body comprises a transparent portion that is substantially optically transparent to the light of the first range of wavelengths. The optically transparent portion of the reaction vessel (110) faces the transparent portion of the body such that light of the first range of wavelengths to and/or from the sample in the reaction vessel (120) can pass through the transparent portion.

Abstract: This document provides methods, devices, and systems for detecting the presence, absence, or amount of one or more analytes. For example, this document provides methods for using graphene-based sensors to detect one or more analytes (e.g., proteins, nucleic acids, intact cells, intact viruses, intact microorganisms, and/or chemicals).

Abstract: A modular analytic system includes a base, at least one fluid sample processing module configured to be removably attached to the base, at least one fluid sample analysis module configured to be removably attached to the base, a fluid actuation module positioned on the base, a fluidic network comprising multiple fluidic channels, in which the fluid actuation module is arranged to control transport of a fluid sample between the at least one sample processing module and the at least one sample analysis module through the fluidic network, and an electronic processor, in which the electronic processor is configured to control operation of the fluid actuation module and receive measurement data from the at least one fluid sample analysis module.

Abstract: Apparatus for controlling motion of liquid droplets. A set of electrode pads is arranged to define one or more tracks over which liquid droplets may be induced to move over a sequence of the electrode pads. A surface over the electrode pads is dielectric, smooth, and slippery to the droplets. In some cases, the smooth surface is formed as a thin layer of a second liquid that is immiscible with the liquid of the droplets. The surface has wetting affinity to the liquid that can be individually varied in a controlled manner by application of voltage to respective electrode pads. A control is designed to alter the wetting characteristic of varying-wettability portions of the surface over respective electrode pads to effect induced motion of the droplets over the surface. The apparatus is designed with the smooth hydrophobic surface open, with no overlying or facing electrode or plate above the droplets.

Abstract: A flow cell having at least one reservoir region containing a liquid reagent. The reservoir region is delimited by a carrier element introduced into an opening in the flow cell together with the reagent, wherein the carrier element seals off the reservoir region from the outside in a fluid-tight manner, and has a vessel and/or capillary structure holding the liquid reagent on the carrier element.

Abstract: Provided are devices and methods for capturing template sample nucleic acids in a spatially specific manner that is coordinated with the original location of the templates in a tissue sample. By preserving spatial information regarding a given sample, the disclosed technology allows for improved diagnostics as well as improved therapeutic decision making for patient care and therapy.

Abstract: A microfluidic device for analyzing samples includes at least two fluidic pathways for receiving samples and at least one capture area. The at least one capture area is configured for a detection unit for measuring light, and is configured to capture light emitted from samples in the at least two fluidic pathways, across the capture area.

Abstract: A reactor microplate that allows for a researcher to perform a multitude of experiment in micro-gravity without risking potential exposure. The microplate includes a planar housing and an at least one chamber-mixing assembly. The chamber-mixing assembly includes a first retaining mechanism, a second retaining mechanism, a mixing channel, and an activation valve. The first retaining mechanism and the second retaining mechanism house solutions for an experiment and are positioned offset to each other, across the planar housing. The mixing channel fluidly couples the first retaining mechanism to the second retaining mechanism. Specifically, the mixing channel traverses into the planar housing from the first retaining mechanism to the second retaining mechanism. The activation valve is mechanically integrated in between the first retaining mechanism, the mixing channel, and the second retaining mechanism to control the flow of fluids in between the first retaining mechanism and the second retaining mechanism.

Abstract: The present invention relates to the field of microfluidics and in particular to devices and methods for sorting objects in microfluidic channels. These devices and methods allow for fast and robust sorting in two-way and multi-way setups. They also enable sorting over extended periods of time.

Abstract: Embodiments of the present disclosure can include a method for convective intracellular delivery including providing cells and molecules to a microchannel having compressive surfaces, wherein the compressive surfaces define compression gaps having a height of from 20 and 80% of the average cell diameter; and a plurality of relaxation spaces disposed between the compressive surfaces; flowing the cell medium through the microchannel, wherein as the cell medium flows through the microchannel, the plurality of cells undergo a convective intracellular delivery process comprising: compressing the plurality of cells, wherein the compressing causes the plurality of cells to undergo a loss in intracellular volume (Vloss); and passing the plurality of cells to a first relaxation space, wherein the plurality of cells undergo a gain in volume (Vgain) and absorb a portion of the plurality of molecules.

Abstract: A variety of devices, systems, kits, and methods are provided for separating or enriching circulating tumor cells in a biological sample such as whole blood. In some aspects, the devices are multi-stage devices including at least a filtering stage, and two separation stages for ferrohydrodynamic separation of magnetically labelled white blood cells and for marker-independent and size-independent focusing of magnetically labeled particles so as to separate or enrich unlabeled rare cells in the biological sample. The devices and methods are, in some aspects, capable of high throughput in excess of 6 milliliters per hour while achieving high separation (>97%) of the unlabeled rare cells.

Abstract: A disc mill assembly of a reducing machine has a housing for housing a first stationary cutting disc in operative interaction with a second rotating cutting disc and separated therefrom by a relative gap distance. The stationary disc is fixed to a housing lid of the housing and the rotating disc is rotatably fixed to a housing body. The relative gap distance between the cutting discs is adjustable by adjusting mechanisms adjusting a relative housing distance between the housing lid and the housing body. A particle size detection analyzer detects the size of particles emanating from the disc mill assembly to generate a detection signal which may be used by the controller to obtain a desired particle size distribution.

Abstract: The invention relates to a milling bowl, in particular for vertical mills, and to the production of such a milling bowl. Milling bowls of this type have hitherto typically been produced from a cast material as a single piece. Due to the increasing size of said milling bowls, said milling bowls can generally only be transported to the destinations by means of special transport. Therefore, the invention creates a milling bowl consisting of assemblies, wherein a double-walled center part formed from two housing shells is provided between a head flange and a base flange. Said center part forms a cavity, which is filled with a curable casting compound such that a rotationally rigid milling bowl is present after the casting compound has been cured.

Abstract: The embodiments of the present disclosure relate generally to subterranean formation operations and, more particularly, to milling oilfield particulates for use in subterranean formation operations. The embodiments provide systems and methods comprising jet mills that can be customized to grind desirably sized crude oilfield particulates, thereby creating operational oilfield particulates, and containerized for ease of use, movement, and shipping.

Abstract: Impact reactor (1) for comminuting composite materials, comprising a cylindrical casing (2), in which a rotor (3) is arranged, and an introducing opening (9) for introducing the composite materials and an extraction opening (8) for discharging the comminuted composite materials, wherein at least one further introducing opening (10) for a cooling medium is provided.

Abstract: A sand separation device for use with wellhead flow, the sand separation device comprising: a housing having a cylinder cone body configured for receiving a fluid mixture including oil, water, gas, and sand; a cyclonic insert arranged within the cylinder cone body; and a tangential inlet configured to redistribute the flow of the fluid mixture and allow for substantially laminar flow of the fluid mixture as it enters the housing and begins separation.

Abstract: A system includes a first magnetic separator, which includes a first housing or is installed in a user's first housing process system, defining a product flow path through which a material may pass, one or more magnets that generate a magnetic field that is positioned within the product flow path to attract metal from the material as the material passes through the product flow path, and a first sensor to detect a presence of captured metal contaminants on the one or more magnets, such as via a measurement of a strength of the magnetic field. The system includes a first controller configured to receive a signal from the first sensor, the signal indicating the presence of the captured metal contaminants on the one or more magnets, and send an instruction related to the signal.

Abstract: The present invention provides a centrifugal separator (14) for separation of at least two components of a fluid mixture which are of different densities. The centrifugal separator (14) comprises a stationary frame (15), a spindle (16) rotatably supported by the frame, a centrifuge rotor 17 mounted to a first end of the spindle to rotate together with the spindle around an axis (X2) of rotation, wherein the centrifuge rotor comprises a rotor casing enclosing a separation space (18) in which a stack (10) of separation discs (1) is arranged to rotate coaxially with the centrifuge rotor, a separator inlet (29) extending into said separation space for supply of the fluid mixture to be separated, a first separator outlet (33) for discharging a first separated phase from said separation space, a second separator outlet (34) for discharging a second separated phase from said separation space.

Abstract: A fluid separation apparatus includes a hydrocyclone (100) having an orifice (134) therein, a housing (202) disposed in the hydrocyclone and having a bore (204), a piston (240) disposed in the bore (204) of the housing (202), and a first annular seal (248) disposed between the housing (202) and the piston (240) and configured to restrict fluid communication between the housing (202) and the piston (240), wherein the piston (240) includes a passage (242) extending through the piston (240) and having a pin (254) coupled to a first end (240a) of the piston, the piston (240) being actuatable to move between a first position (260) where the pin (254) is clear of the orifice (134) of the hydrocyclone, and a second position where the pin (254) is disposed in the orifice (134), wherein, the piston (240) is configured such that as the piston is actuated from the first position to the second position, fluid is permitted to flow into the passage (242) of the piston (240) from the bore (204) of the housing (202).

Abstract: A multi-function shower head for automatically adjusting a water flow spray pattern upon interrupting water flow.

Abstract: Devices deliver the content of an aerosol, and are used in powder-actuated tools. A spray nozzle includes a cylindrical housing having, at a first end, with a base having a mounting bore that extends inside said housing so as to receive a barrel of a powder-actuated tool. The nozzle is equipped with a securing means. The base includes lobes that lie opposite one another in a single plane. A peripheral section of the second end of the housing is located on the same side as one of these lobes and has a curved projection with a rounded outer surface and an upward taper to form a common top surface with an additional cylindrical projection partially embedded into the inner surface of the curved projection. A V-shaped groove in communication with an axial opening of the second end of the housing extends on a free side of the additional projection.

Abstract: A dispensing head with a staged swirling chamber for a dispensing system includes a spraying nozzle including a dispensing orifice and a swirling chamber opening into the dispensing orifice, the swirling chamber including a converging portion, and extending along an axis between an upstream end and a downstream end in the direction of displacement of the product, and an anvil including a core provided with a peripheral wall, that is housed inside the swirling chamber, and forming with the converging portion at least one fluidic path in which the product circulates, the converging portion including an inner wall of the nozzle, the inner wall and/or the peripheral wall of the core being provided with a plurality of steps, each step being defined by a transverse wall that extends in a plane secant to the axis and a longitudinal wall substantially parallel to the axis, the steps forming obstacles in the fluidic path.