In some example embodiments, a system includes a drill string having a drill bit. The drill string extends through at least part of a well bore. The system also includes a first vibrational sensor, positioned on the drill bit to measure, at a first location on the drill string, an amplitude of one or more of an axial vibration and a lateral vibration. The system also includes a second vibrational sensor, positioned above the drill bit and on the drill string. The second vibration sensor is to measure, at a second location on the drill string, one or more of an axial vibration and a lateral vibration. The system includes a processor unit to determine a type of vibration based on a comparison of the amplitude at the first location to the amplitude at the second location, wherein the type of vibration is at least one of bit whirl of the drill bit and a while of a bottom hole assembly that is part of the drill string.

In one aspect, an apparatus for drilling a wellbore into an earth formation is disclosed, which apparatus, according to one embodiment, may include a drill string configured to be conveyed into a wellbore, wherein an annulus is formed between the drill string and a wellbore wall, a first flow device configured to circulate a first fluid from an annulus to a bore of the drill string, and a second flow device positioned downhole of the first flow device, the second flow device configured to circulate a second fluid from the bore of the drill string to the annulus.

According to an embodiment, a drilling fluid comprises: water and a set accelerator, wherein the drilling fluid has a 10 minute gel strength of less than 20 lb*ft/100 sq ft, wherein the drilling fluid has a density in the range of about 9 to about 14 pounds per gallon, wherein the drilling fluid remains pourable for at least 5 days, and wherein when at least one part of the drilling fluid mixes with three parts of a cement composition consisting of water and cement, the drilling fluid cement composition mixture develops a compressive strength of at least 1,200 psi. According to another embodiment, a method of using the drilling fluid comprises the steps of: introducing the drilling fluid into at least a portion of a subterranean formation, wherein at least a portion of the drilling fluid is capable of mixing with a cement composition.

Diamond bonded constructions comprise a diamond body attached to a substrate, wherein the body includes a first diamond bonded volume, and a second diamond bonded volume attached thereto. The second volume may be provided in the form of a powder or a presintered mass prior to attachment, and the first volume may be provided in the form of presintered pieces when combined with the second volume. The first volume diamond volume content is greater than about 94 percent, and is the same or greater than that of the second volume. The first volume is sintered during a first HPHT process, and the second volume is sintered and/or attached to the first volume during a second HPHT process. The first HPHT pressure is greater than the second HPHT pressure. The substrate is not an infiltration substrate used to form the first diamond volume. The diamond body may be thermally stable.

Systems and methods for processing drilling data. One embodiment provides a method comprising building user-designed contexts (which can be designated as built-in contexts) for drilling structures. The method also comprises orchestrating module execution within the user-designed contexts. The method further comprises providing data from the user-designed contexts to such modules via an interface. Some methods include monitoring drilling data to detect events (for instance departure from a pseudolog) and orchestrating module execution responsive thereto. The method can include exposing the orchestration of the execution of the module instances as a service. Moreover, some embodiments provide extra-contextual application program interfaces. In addition, or in the alternative, some embodiments schedule the orchestration of the modules based on declarations related to the inputs and/or outputs of the modules.

A method for reducing the friction forces between tubulars, for example coiled tubing in casing includes mixing a selected suspending agent and surfactant and polymer particles in oil, then adding the mixture to water and pumping the mixture down the tubing. The mixture is particularly useful in coiled tubular drilling inside casing of an oil or gas well. The formulation has also been found to reduce corrosion on metal surfaces.

An adjustable bent drilling tool capable of changing in situ drilling direction to facilitate horizontal drilling. The drilling tool may be controlled from the surface and eliminates the need to bring the tool to the surface for reconfiguration. In one embodiment, the drilling tool utilizes a communications module to communicate with upstream sections of the tool. The communications module is connected to a programmable electronic control module which controls an electric motor. A hydraulic valve assembly follows the control module, which receives input signals and controls a pilot piston between two fixed points of a mid-assembly typically located adjacent to and downstream of the hydraulic valve assembly on the drill tool. A lower assembly is attached to the drill tool immediately following the mid-assembly, and provides both a safety release sub-assembly as well as a bendable sub-assembly which directs the adjustable drill tool to change drilling angle and direction.

A detector for detecting ionizing radiation comprises a scintillator 10 selected to emit light in response to incidence thereon of radiation to be detected, at least one detector 16 for detecting said emitted light, and at least one optical waveguide 12 for transmitting said emitted light to said detector 16. The optical waveguide typically comprises a flexible solid or hollow fiber that can be incorporated into a flexible mat or into a fiber-reinforced structure, so that the detector is integrated therewith.

A sensor includes a collector, an emitter and a base-region barrier formed as an inverted bipolar junction transistor having a base substrate forming a base electrode to activate the inverted bipolar junction transistor. A level surface is formed by the collector, the emitter and the base-region barrier opposite the base substrate such that when the level surface is exposed to charge, the charge is measured during operation of the bipolar junction transistor.

A particle beam sensor comprising: scattering means providing a surface for intercepting obliquely a path of a particle beam thereby to permit a scattering of particles from the particle beam by the scattering means; sensor means responsive to receipt of one or more said scattered particles to generate a sensor signal; aperture mask means arranged between the scattering means and the sensor means to present to the scattering means a screen opaque to said scattered particles and having at least one aperture through which an unobstructed view of the scattering means is provided to the sensor means, the aperture (s) thereby permitting selection of all of those particles scattered by the scattering means which may be used to form at the sensor means an image representative of at least a part of a foot print cast by the particle beam upon the scattering means. By scattering particles from a sectional area of a particle beam, scattered beam particles can be used more efficiently compared to existing techniques.

This invention relates to a two-dimensional detection system for neutron radiation comprising a means (1) for emitting a neutron beam (10), a support means (2) adapted for receiving a sample (3), a photoemission means (5) adapted for being activated by a neutron radiation, a cooled low light level charge-coupled detection device (7). The emission means (1) emits a monochromatic neutron beam (10). The system further comprises a filter means (4), the filter means (4) being located between the support means (2) and the photoemission means (5) and being adapted for trapping at least a substantial part of the monochromatic neutron beam transmitted (12) by the sample (3), and an amplification means (6) located upstream the charge-coupled detection device (7) and coupled with the charge-coupled detection device (7).

A method of bunch length compression method for a free electron laser (FEL) that avoids parasitic compressions by 1) applying acceleration on the falling portion of the RF waveform, 2) compressing using a positive momentum compaction (R56>0), and 3) compensating for aberration by using nonlinear magnets in the compressor beam line.

A system for measuring properties of a surface under test with surface waves includes a surface wave network including a dielectric substrate, a reactive grid of a plurality of metallic patches on a first surface of the dielectric substrate, a plurality of electronic nodes on the first surface of the dielectric substrate, and a ground plane on a second surface of the dielectric substrate permeable to RF fields of the surface waves, and a controller configured for causing a respective one of the electronic nodes to transmit at least one surface wave and configured for collecting data for signals received by at least one other of the plurality of electronic nodes.

Examples of the present invention include apparatus and methods for monitoring aging of an item. A solid-state structure is located within, adjacent to, or otherwise proximate the item, the solid-state structure including nanostructures. The electrical resistance and/or magnetization of the solid-state structure is determined to determine the degree of aging of the item. In representative examples, the solid-state structure includes nanostructures of a metal, such as a ferromagnetic metal, within a non-magnetic matrix, such as a semimetal, semiconductor, or insulator.

A camera array, an imaging device and/or a method for capturing image that employ a plurality of imagers fabricated on a substrate is provided. Each imager includes a plurality of pixels. The plurality of imagers include a first imager having a first imaging characteristics and a second imager having a second imaging characteristics. The images generated by the plurality of imagers are processed to obtain an enhanced image compared to images captured by the imagers. Each imager may be associated with an optical element fabricated using a wafer level optics (WLO) technology.

An approach is disclosed for acquiring multi-sector computed tomography scan data. The approach includes activating an X-ray source during heartbeats of a patient to acquire projection data over a limited angular range for each heartbeat. The projection data acquired over the different is combined. An image having good temporal resolution is reconstructed using the combined projection data.

A method and apparatus for acquiring data from a mass spectrometer and its transmission to a computer system including a data acquisition engine, a network interface and a throughput optimization module which includes a ring buffer and a protocol stack. A compression engine may be provided between the acquisition engine and the ring buffer. The ring buffer is configured as a number of segments containing portions of memory matching the size of data words from the acquisition engine. When a segment is full of data corresponding to the words, or is partially full and has received data containing an end of scan marker, the number of words in the segment is written into a header word in the segment and the data in that segment are moved to the protocol stack. Subsequent data is received by the next segment in the buffer.

An airflow-organization testing method for a clean room and a system using the same method are disclosed. The airflow-organization testing method for a clean room uses a thermal imaging device to detect a sample gas-flow formed by a sample gas in the clean room, and the sample gas has a temperature difference from ambient air. The airflow-organization testing system for a clean room includes a sample gas supplier and a thermal imaging device, and the thermal imaging device can continuously detect a spatial position of the sample gas and display it on a display, thereby improving detection precision and expanding detection range.

It is an object to provide a photoelectric conversion device whose power consumption and a mounting area are reduced and yield is improved and further to provide a photoelectric conversion device whose number of manufacturing processes and manufacturing cost are reduced. A photoelectric conversion device includes a photoelectric conversion element for outputting photocurrent corresponding to illuminance, and a resistor changing resistance corresponding to illuminance. In the photoelectric conversion device, one terminal of the photoelectric conversion element and one terminal of the resistor are electrically connected in series; the other terminal of the photoelectric conversion element is connected to a high power supply potential; the other terminal of the resistor is connected to a low power supply potential; and a light intensity adjusting unit is provided on a light reception surface side of the photoelectric conversion element or the resistor to adjust illuminance.

A gasifier comprises an internal chamber, a slag collection region, a slag passageway, a slag breaker, and an actuator. The internal chamber comprises a main combustion region that is configured and adapted to gasify fuel. The slag collection region is located beneath the main combustion region. The slag passageway operatively connects the main combustion region to the slag collection region. The slag breaker comprises a face that is movable relative to the internal chamber. The face is configured and adapted to move within the slag passageway in a manner such that the face contacts and mechanically breaks solidified slag into chunks of solidified slag that then fall into the slag collection region. The actuator is connected to the slag breaker and is configured and adapted to move the face of the slag breaker.

Sorbent components containing halogen, calcium, alumina, and silica are used in combination during coal combustion to produce environmental benefits. Sorbents such as calcium bromide are added to the coal ahead of combustion and other components are added into the flame or downstream of the flame, preferably at minimum temperatures to assure complete formation of the refractory structures that result in various advantages of the methods. When used together, the components: reduce emissions of elemental and oxidized mercury; increase the level of Hg, As, Pb, and/or CI in the coal ash; decrease the levels of leachable heavy metals (such as Hg) in the ash, preferably to levels below the detectable limits; and make a highly cementitious ash product.

Apparatus for separating ash particles from a flue gas. The apparatus includes a screen that has a plurality of semi-elliptical cylinder surfaces. The semi-elliptical cylinder surfaces having holes through which said flue gas flows and through which the ash particles will not pass. The screen has a single layer for performing the separation in a manner such that the ash particles fall away from the screen and collect outside of the screen. A method of reducing velocity of a flue gas passing through screening apparatus for separating flue gas from ash particles. The method includes replacing a first screen of the screening apparatus with a second screen that has a plurality of semi-elliptical cylinder surfaces.

An aspect of the present invention is a method of processing a waste material that contains mercury or a mercury compound, and chlorine or a mercury chloride, the method including a step of adding a chlorine scavenger to the waste material, and stowing the waste material in a treatment vessel; and a step of subjecting the waste material to a blasting treatment by fitting an explosive to the treatment vessel and detonating the explosive inside a pressure-proof container.

A slag remover for discharging combustion residues of an incineration plant comprises a trough, which has a trough housing having two side walls, which define the trough width, and having a trough bottom, and which is intended to collect the combustion residues evacuated from a combustion chamber of the incineration plant. The trough further comprises at least two push rams for pushing the combustion residues out of the trough, and a shaft rotatably mounted in two shaft bearings and on which at least one drive lever cooperating with a cylinder-piston unit and at least two output levers connected to respectively one of the push rams are disposed in a rotationally secure manner. The cylinder-piston unit is here designed such that the push rams move back and forth between a retracted position and an extended position. The drive lever is disposed between two output levers.

An ash basket can act as a sieve or strainer, allowing a user to lift out the charcoal from a kamado grill, clean out the ash, and place the ash basket back into the grill for future use. The ash basket retains larger pieces of charcoal that can be reused, while allowing the ash to pass through to a bottom plate of the grill. The bottom plate has openings to permit the ash to fall to an ash collection chamber. Without the ash basket, pieces of charcoal can block the openings in the bottom plate, making ash collection difficult. Moreover, with the openings blocked, proper air flow through the openings. Finally, the ash basket creates and additional air space that covers the entire surface of the interior walls by separating the ash from the wall, improving air flow, which is critical to the kamado grill design.

Apparatus and methods are disclosed for rapidly counteracting a transient low-pressure condition, that can occur intermittently in the exhaust section of a power plant or other such industrial facility upstream of exhaust fans as a result of an event that interrupts the generation and/or flow of exhaust gases, using jet nozzles disposed in the exhaust section and connected to a source of pressurized air or other suitable momentum material. By orienting the jet nozzles in a direction generally opposite to the flow of exhaust gas and actuating the system to release a burst of compressed air, for example in the event of a power plant interruption, the low-pressure condition can be ameliorated preventing damage to the exhaust section.

A two stage refuse gasification combustion system for processing refuse is disclosed. The system may contain features such as an advancer, a first and second gasifier, a gas regulator, and a post combustor. Additionally, methods for regulating gas and advancing refuse through a two stage refuse gasification combustion system are disclosed.

Methods of combustion include metering a substantially explosible powder into an oxidizing gas using a positive displacement powder dispersion device to suspend the powder in the gas and directing the powder in the gas to form a controlled stream of a moving explosible powder dispersion. In some embodiments, the method further includes igniting the dispersion with an ignition source to produce a stationary deflagrating combustion wave and sustaining combustion by continuing to meter the powder into the gas. In other embodiments, the method further includes adjusting a nozzle velocity of the dispersion to reflect properties of the dispersion to create a sustainable flame and igniting the dispersion to produce a stationary deflagrating wave of the dispersion. In other embodiments, the method further includes igniting the dispersion in a combustion area to produce a stationary deflagrating wave such that a conductive heat transfer from combustion brings the powder to combustion temperature.

The burner preferably exclusively burns substantially explosible solid fuels and preferably has instant ON-OFF thermostat control, wastes no energy preheating the enclosure or external air supply, achieves stable combustion the moment the powder-air mix is ignited in our burner, is used in the upward vertical mode except for oil burner retrofits, burns a solid fuel in a single-phase regime as if it were a vaporized liquid or gas, is designed to complete combustion within the burner housing itself rather than in a large, high temperature furnace enclosure which it feeds, has an ultra-short residence time requirement, is a recycle consuming burner with self-contained management of initially unburned particles, is much smaller, simpler and lower cost, has a wider dynamic range/turndown ratio, is more efficient in combustion completeness and thermal efficiency, and operates with air-fuel mix approximately at the flame speed.

A gasification reactor for processing organic waste in batches comprises a primary gasification reactor (62) that includes a primary gasification chamber (18) and a surrounding combustion chamber (19), a secondary gasification chamber (21), a synthesis gas decontamination unit (42) and a combustible gas selector (41). The waste is loaded into the primary gasification chamber through a latched opening and heated from the combustion of a fuel in the combustion chamber (19) to convert the waste to a synthesis gas. The gasification chamber (18) has an intake (20) for introducing pre-heated process air (1) therein. The combustion chamber operates either with a conventional fuel (9) or with the produced synthesis gas (6). The secondary gasification chamber (21) thermally treats the synthesis gas (2) to eliminate tars. The decontamination unit (42) scrubs the synthesis gas of contaminants including particulates and acid gases. The clean synthesis gas (6) is directed to the combustible gas selector (41) which selectively feeds either the combustible fluid (9) or the synthesis gas (6) to the burner (40).

Improved silicon solar cells, silicon image sensors and like photosensitive devices are made to include strained silicon at or sufficiently near the junctions or other active regions of the devices to provide increased sensitivity to longer wavelength light. Strained silicon has a lower band gap than conventional silicon. One method of making a solar cell that contains tensile strained silicon etches a set of parallel trenches into a silicon wafer and induces tensile strain in the silicon fins between the trenches. The method may induce tensile strain in the silicon fins by filling the trenches with compressively strained silicon nitride or silicon oxide. A deposited layer of compressively strained silicon nitride adheres to the walls of the trenches and generates biaxial tensile strain in the plane of adjacent silicon fins.

Methods and apparatus for converting electromagnetic radiation, such as solar energy, into electric energy with increased efficiency when compared to conventional solar cells are provided. A photovoltaic (PV) device generally includes a window layer; an absorber layer disposed below the window layer such that electrons are generated when photons travel through the window layer and are absorbed by the absorber layer; and a plurality of contacts for external connection coupled to the absorber layer, such that all of the contacts for external connection are disposed below the absorber layer and do not block any of the photons from reaching the absorber layer through the window layer. Locating all the contacts on the back side of the PV device avoids solar shadows caused by front side contacts, typically found in conventional solar cells. Therefore, PV devices described herein with back side contacts may allow for increased efficiency when compared to conventional solar cells.

A photoelectric conversion element comprising a substrate, a first electrode, a photoelectric conversion layer comprising a semiconductor and a sensitizing dye, a hole transport layer and a second electrode, wherein the hole transport layer comprises a polymer having a repeat unit represented by Formula (1) or (2),

Photo-field-effect transistor devices and associated methods are disclosed in which a photogate, consisting of a quantum dot sensitizing layer, transfers photoelectrons to a semiconductor channel across a charge-separating (type-II) heterointerface, producing a sustained primary and secondary flow of carriers between source and drain electrodes. The light-absorbing photogate thus modulates the flow of current along the channel, forming a photo-field effect transistor.

A resin composition, a multi-layered film, a backsheet for photovoltaic modules, a method thereof, and a photovoltaic module are provided. The multi-layered film including a coating layer including a fluorine-based polymer has an excellent durability and weather resistance, and also exhibits high interfacial adhesive strength to a substrate since the multi-layered film is formed by coating a cured product of the resin composition including the fluorine-based polymer, an acrylic polymer including a thermosetting functional group, and a heat-curing agent on the substrate. In addition, drying can be performed at a low temperature during the manufacture of the multi-layered film so that the manufacturing costs can be decreased, productivity can be increased, and the deterioration of the product due to heat modification, heat shock, and the like, can be prevented. The multi-layered film can be effectively used as a backsheet for various photovoltaic modules.

An organic compound and a photoelectric conversion device containing the organic compound are disclosed. The organic compound and device realize high photoelectric conversion efficiency, low dark current and high-speed responsivity. It has been found that when this organic compound and an n-type semiconductor are used in combination, high-speed responsivity can be realized while maintaining high heat resistance, an aspect of which has not been seen when the connection part between a donor part and an acceptor part is a phenylene group.

An improved method and apparatus for thermal-to-electric conversion involving relatively hot and cold juxtaposed surfaces separated by a small vacuum gap wherein the cold surface provides an array of single charge carrier converter elements along the surface and the hot surface transfers excitation energy to the opposing cold surface across the gap through Coulomb electrostatic coupling interaction.

A layered compound-metal particle composite 3 is obtained by the addition, to an organically modified layered compound 1 formed by the intercalation of organic ions between layers of a layered compound, of both an aqueous colloidal metal solution 2 in which metal particles are dispersed as a metal colloid in water, and a nonaqueous solvent which is a poor solvent for the metal colloid and has an excellent ability to swell the organically modified layered compound 1.

The present invention provides a dye-sensitized solar cell which enhances an area of a photo electrode by arranging metal wires on a surface of a transparent substrate or a transparent conductive layer without degrading a transparency of the solar cell, allowing the metal wires to act as a collector electrode exclusively or together with a metal electrode.

A crack resistant solar cell module includes a protective package mounted on a frame. The protective package includes a polyolefin encapsulant that protectively encapsulates solar cells. The polyolefin has less than five weight percent of oxygen and nitrogen in the backbone or side chain. In other words, the combined weight percent of oxygen and nitrogen in any location in the molecular structure of the polyolefin is less than five. The polyolefin also has a complex viscosity less than 10,000 Pa second at 90° C. as measured by dynamic mechanical analysis (DMA) before any thermal processing of the polyolefin. The protective package includes a top cover, the encapsulant, and a backsheet. The solar cell module allows for shipping, installation, and maintenance with less risk of developing cracks on the surfaces of the solar cells.

A separate connection device (40) intended to be inserted between a metal frame (3), of an electrical component (1), and a metal supporting structure (20) in order to connect, electrically and separately, the frame to the supporting structure. The connection device (40) comprises a metal blade manufactured from spring steel which comprises two self-connecting end areas (45, 46) arranged in separate planes and comprising a set of sharp teeth (47) arranged in order to be embedded within the metal material and formed on a folded section of the metal blade so that the sets of teeth (37, 47) extend in opposite directions and in planes intended to intersect the planes of the frame (3) and of the supporting structure (20) when the connection device is mounted.

The present disclosure relates to gel-type polymer electrolyte for a dye-sensitized solar cell, a dye-sensitized solar cell comprising the gel-type polymer electrolyte, and a method for manufacturing the dye-sensitized solar cell.

The present invention provides a photoelectric conversion material comprising a fullerene derivative represented by the formula C60(R1)5(R2), wherein each R1 independently represents an organic group having a substituent; and R2 represents a hydrogen atom or a substituted or unsubstituted C1-C30 hydrocarbon group. Further, the present invention also provides a photoelectric conversion device having a self-assembled monomolecular film of the photoelectric conversion material, and a solar cell having the photoelectric conversion device.

A conductive paste may include a conductive component and an organic vehicle. The conductive component may include an amorphous metal. The amorphous metal may have a lower resistivity after a crystallization process than before the crystallization process, and at least one of a weight gain of about 4 mg/cm2 or less and a thickness increase of about 30 μm or less after being heated in a process furnace at a firing temperature.

According to example embodiments, a conductive paste includes a conductive component that contains a conductive powder and a titanium (Ti)-based metallic glass. The titanium-based metallic glass has a supercooled liquid region of about 5K or more, a resistivity after crystallization that is less than a resistivity before crystallization by about 50% or more, and a weight increase by about 0.5 mg/cm2 or less after being heated in a process furnace at a firing temperature. According to example embodiments, an electronic device and a solar cell may include at least one electrode formed using the conductive paste according to example embodiments.

A solar-cell sealant that has excellent properties such as transparency, flexibility, adhesiveness, heat resistance, appearance, cross-linking characteristics, electrical characteristics, and calenderability. A solar-cell sealant that contains an ethylene/α-olefin/unconjugated-polyene copolymer satisfying requirements (a1) through (a3). Requirement (a1) is that constituent units derived from ethylene constitute 80-90 mol %, constituent units derived from C3-20 α-olefin constitute 9.99-19.99 mol %, and constituent units derived from an unconjugated polyene constitute 0.01-5.0 mol % of said copolymer. Requirement (a2) is that the MFR of said copolymer, as measured in accordance with ASTM D1238 at 190° C. under a 2.16 kg load, be at least 2 g/10 min. and less than 10 g/10 min. Requirement (a3) is that the Shore A hardness of said copolymer, as measured in accordance with ASTM D2240, be 60 to 85.

Methods of forming a photovoltaic structures including nanoparticles are disclosed. The method includes electrospray deposition of nanoparticles. The nanoparticles can include TiO2 nanoparticles and quantum dots. In an example, the nanoparticles are formed on a flexible substrate. In various examples, the flexible substrate is light transparent. Photovoltaic structures and apparatus for forming photovoltaic structures are disclosed.

A printing material web processing machine, in particular a web-fed rotary offset press, has at least one press cylinder for printing the web, a dryer disposed downstream of the press cylinder, which guides the web along a path, and at least a first pull roll disposed downstream of the dryer to convey the web along the path with a given tensile stress. The web processing machine further has a first apparatus disposed downstream of the press cylinder and upstream of the dryer for separating the web from the press cylinder, and a second apparatus for driving the first pull roll, which drives the first pull roll at a rotational speed that is reduced as compared with the rotational speed of the press cylinder.

A method is disclosed for controlling at least one machining device which is coupled to a machine tool by means of an encoder signal, the machine tool having at least one motion control device. In order to improve the accuracy of the encoder connection, at least one additional variable which characterizes the transport is digitally transmitted from the motion control device to the at least one machining device and is used to correct the encoder signal.

A feeding and reversing mechanism for a strapping machine includes a forward-reverse wheel assembly and a tension wheel assembly which are mounted on a base and arranged in such a way to provide larger contact areas between a strapping band and the two wheel assemblies. The feeding and reversing mechanism further includes first and second spring units. The first spring unit helps to keep a suitable gap between an active wheel and a passive wheel of the tension wheel assembly for the strapping band to pass through. The second spring unit helps to move the passive wheel toward the active wheel of the tension wheel assembly, so that the strapping band can be clamped between the passive wheel and the active wheel tightly to facilitate reversing and tightening of the strapping band.