A method for managing a drilling operation, including generating, by a first sensor and a second sensor of a bottom hole assembly (BHA), a first time based data log and a second time based data log, respectively, representing a borehole parameter along a drilling trajectory, determining, by a computer processor of the BHA and during the drilling operation, a time shift by comparing the first time based data log and the second time based data log, where offsetting the first and second time based data logs by the time shift maximizes a correlation factor of the first and second time based data logs, and determining, within a pre-determined time period from generating the first and second time based data logs, a drilling speed based on the time shift and a pre-determined distance between the first sensor and the second sensor.

Apparatus and method for automated drilling of a borehole in a subsurface formation. In one embodiment, a method includes selecting at least one control variable. A drilling performance objective having a value that is influenced by drilling of the borehole using the at least one control variable is defined. A first interval of the borehole is drilled maintaining the at least one control variable at a first value. A second interval of the borehole is drilled maintaining the at least one control variable at a second value. A third interval of the borehole is drilled maintaining the at least one control variable at a third value. The third value is selected based on a comparison of the values of the drilling performance objective while drilling the first interval and second interval to a predetermined optimal value of the drilling performance objective.

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.

A method of monitoring a well for unwanted formation fluid influx is disclosed. Measurements of well outflow are acquired during a period in which drilling operations are performed for the well. Occurrences of stagnant flow events during the period are determined. An outflow signature is generated from the well outflow measurements for each stagnant flow event. The outflow signatures are displayed sequentially in time of occurrence. Each outflow signature is analyzed for an anomaly.

Nozzles for drilling tools, such as rotary-type drag bits and roller cone bits, a drilling tool and drilling assembly comprising nozzles, and methods of conveying drilling fluid through a nozzle for use in drilling subterranean formations are provided. A nozzle may include a substantially cylindrical nozzle body having an axis and an inlet port with a primary passage extending therethrough, and at least one secondary passage that diverges from the primary passage at an exit port.

Expandable apparatus for use in subterranean boreholes include at least one member configured to move between a retracted position and an extended position. A latching member disposed in the tubular body may selectively retain the at least one member in the retracted position. Methods of operating an expandable apparatus include securing at least one member of the expandable apparatus in a retracted position by engaging an inner wall of a tubular body with at least one latch member disposed in at least one aperture formed in a latch sleeve.

Expandable apparatus for use in subterranean boreholes include at least one member configured to move between a retracted position and an extended position. Components of the expandable apparatus may include at least one surface for removing debris proximate to the tubular body. Components of the expandable apparatus may be configured to enable the expandable apparatus to increase a diameter of a subterranean borehole by greater than twenty percent. Components of the expandable apparatus may be configured to restrict fluid flow to nozzle assemblies. The expandable apparatus may include a protect sleeve having a push sleeve disposed therein. Methods of operating an expandable apparatus may include removing debris with a surface of the expandable apparatus. Methods of operating an expandable apparatus may also include selectively flowing fluid to nozzle assemblies.

A method for estimating an inclination and azimuth at a bottom of a borehole includes forming a last survey point including a last inclination and a last azimuth; receiving at a computing device bending moment and at least one of a bending toolface measurement and a near bit inclination measurement from one or more sensors in the borehole; and forming the estimate by comparing possible dogleg severity (DLS) values with the bending moment value.

A tracking system for tracking an eye including a light source projecting light toward a display surface in a sequential pattern, one or more reflectors associated with an optical device, where the one or more reflectors reflect the pulses of light from the display source, one or more photo detectors, where the photo detectors detect reflected pulses of light from the light source, and a system that measures pulse timing relative to horizontal and vertical pattern to compute a gaze angle of the eye.

A rugged scintillation crystal assembly includes several scintillator crystals, which are optically coupled to each other by resilient optical-coupling material such as silicone pads and/or grease. The scintillator crystals are configured to collectively emit optical signals. Such a stack may combine the advantages of both a long form-factor for the overall assembly with the ruggedness of the assembly's component short crystals.

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.

In a pattern inspection of a semiconductor circuit, to specify a cause of a process defect, not only a distribution on and across wafer of the number of defects but also more detailed, that is, the fact that how many defects occurred where on the semiconductor pattern is needed to be specified in some cases. Accordingly, the present invention aims to provide an apparatus capable of easily specifying a cause of a process defect based upon a positional relationship of a distribution of defect occurrence frequency and a pattern. The apparatus includes: a charged particle beam optical system for detecting secondary charged particles by irradiating the charged particle beam to the sample; an image processing unit for, based upon a plurality of images to be inspected that are obtained by the secondary charged particles, obtaining an occurrence frequency of defect candidates for each of predetermined regions inside the detected image; and a display unit for displaying the distribution of the occurrence frequency of the defect candidates so that a positional relationship to the pattern is recognized.

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.

Systems and methods are disclosed herein to a radiation safety system comprising radiation emitting medical equipment; a radiation safety system controller connected to the radiation emitting medical equipment through a first communication means configured to determine a number of people within a radiation room housing the radiation emitting medical equipment and prevent the radiation emitting medical equipment from performing radiation emitting functions if the radiation safety system controller determines that more people than a maximum allowed number of people are presently in the radiation room; and a scanner connected to the radiation safety controller through a second communication means configured to detect people in the radiation room and communicate to the radiation safety system controller that a person has been detected.

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.

An apparatus comprises a plasma flood gun for neutralizing a positive charge buildup on a semiconductor wafer during a process of ion implantation using an ion beam. The plasma flood gun comprises more than two arc chambers, wherein each arc chamber is configured to generate and release electrons into the ion beam in a respective zone adjacent to the semiconductor wafer.

A detection apparatus configured to detect soft X-ray radiation, includes a conversion unit and a circuit unit disposed on a semiconductor substrate. The conversion unit has a plurality of conversion elements that convert the soft X-ray radiation incident on the semiconductor substrate into electric charge. The circuit unit has an amplifier transistor that amplifies and outputs a signal supplied from the conversion unit. A shielding unit is disposed above the circuit unit. The shielding unit blocks the soft X-ray radiation incident on the circuit unit. Preferably, the soft X-ray shielding coefficient of a material that forms the shielding unit is higher than the soft X-ray shielding coefficient of each of aluminum and copper. Alternatively, a material that forms the shielding unit has an atomic number higher than or equal to 70.

A system of investigating aberrations in a charged particle lens system, wherein a charged particle beam is directed from a multitude of directions through a pivot point on a sample stage. An image figure is recorded for each of multiple focus settings at each beam direction setting, creating a set of registered images. This set of images is compared to reference images to derive aberrations present in the lens system without the use of an amorphous sample present.

An arrangement for, and a method of, electro-optically reading a target by image capture, employ an aiming assembly for projecting an aiming light pattern on the target that is located within a range of working distances relative to a housing, an imaging assembly for capturing an image of the target and of the aiming light pattern over a field of view, and a controller for determining a distance of the target relative to the housing based on a position of the aiming light pattern in the captured image, for determining a scanning resolution based on the determined distance, for comparing the determined scanning resolution with a scanning resolution setting, and for processing the captured image based on the comparison.

In one aspect, an optical device comprises a monolithic optical module which includes a first total internal reflection (TIR) surface, a second TIR surface adjacent the first TIR surface, and a first optical port aligned with the first internal optical beam dividing interface. An interface between the first TIR surface and the second TIR surface forms a first internal optical beam dividing interface. An exterior surface of the first TIR surface and an exterior surface of the second TIR surface form a generally V-shaped notch on the monolithic optical module. A first optical beam entering the monolithic optical module through the first optical port and incident on the first internal optical beam dividing interface is partially reflected by the first TIR surface to travel in a first direction as a second optical beam and partially reflected by the second TIR surface to travel in a second direction as a third optical beam. The second direction is generally opposite to the first direction.

The present invention is directed to additives for coal-fired furnaces, particularly furnaces using a layer of slag to capture coal particles for combustion. The additive(s) include iron, mineralizer(s), handling aid(s), flow aid(s), and/or abrasive material(s). The iron and mineralizers can lower the melting temperature of ash in low-iron, high alkali coals, leading to improved furnace performance.

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.

An exemplary embodiment of the present invention provides an induced-draft injection system comprising an injection line in fluid communication with a duct under negative pressure, a particulate storage containing particulate, and a feeder receiving the particulate from the particulate storage and feeding the particulate to the injection line. The negative pressure in the duct supports the transportation of at least a portion of the particulate through the injection line and into the duct. Inside the duct, a binding portion of the particulate is bound to a portion of mercury in a flue gas passing through the duct, thus enabling a portion of the mercury to be filtered out of the flue gas.

The inventive technology includes methods and apparatus for the generation and application of segregated catalytic additives for the pre-combustion treatment of carbonaceous fuel and/or feedstocks. The application of such segregated additives results in the reduction of environmentally harmful emissions during combustion as well as gasification processes. Specifically, pre-combustion treatment of carbonaceous materials with the inventive additives results in the reduction of NOx and/or mercury emissions by least 20% and 40% respectively.

A pulverized coal burner and a pulverized coal boiler. The coal burner comprises a primary air cylinder (111) and a pulverized coal concentration device (112). The coal concentration device (112) makes the concentration of the coal flow gradually decrease from inside to outside along the radial direction, with respect to an axis (100) of the primary air cylinder (111). The coal burner further comprises a coal separating cylinder (113) and a coal guiding cylinder (114) located downstream of the device (112), the rear end of the cylinder (113) is connected with the front end of the coal guiding cylinder (114). The outlet of the cylinder (114) has a conical expansion portion (1141). The coal burner further comprises a divergent nozzle (115) connected with the rear end of the primary air cylinder (111) and whose cross-sectional area gradually increases along the flow direction of the coal flow.

This invention provides a system and method for efficiently and completely combusting oil in mixture with particulate solids. A furnace (kiln) having a feed nozzle with a lead screw drives the mixture from a feed hopper. This nozzle includes forced-air jets/ports at its tip providing makeup air and allowing atomization of the mixture. The nozzle thereby directs the mixture into a rotating combustion chamber that is tilted downwardly from the front toward a solid waste outlet port at the rear. Uncombusted fuel and air backflow to an upper, secondary chamber near the primary chamber front, and are completely combusted at a high temperature. Gasses exit a flue that can include a heat exchanger. This heat exchanger can be operatively connected to a heating device or other mechanism that converts the heat into usable energy. The nozzle can include a cone with axially tilted air ports about its perimeter.

A carbon fuel combustion process, employing an air gas separation unit, a combustion unit operating either with air or with an oxidizer leaner in nitrogen than air, coming from the air gas separation unit, and a unit for compressing and/or purifying the CO2 coming from the combustion flue gas, wherein the power consumed by the air gas separation unit and/or the flow of oxygen produced by the air gas separation unit and/or the capture of the CO2 coming from the combustion flue gas are variable over time is presented.

A method is illustrated and described for reducing unwanted substances by injecting a reactant into a flue gas of a steam generator. In order that the reactant can also be used in larger steam generators and/or combustion chambers, a method is proposed, in which the reactant is injected into the combustion chamber of the steam generator via a reactant opening of a multi-component nozzle, in which an enveloping medium is injected into the combustion chamber through at least one enveloping medium opening arranged outside the reactant opening, and in which the enveloping medium at least partly envelops the reactant in the combustion chamber and in this way at least partly shields the reactant from the flue gas.

A coal nozzle assembly for a pulverized coal burner includes a diffuser. A flow conditioner also may be used with the assembly. The assembly conditions the coal/air flow before the coal/air flow is introduced to the furnace. The flow conditioner directs the coal into the diffuser where it is swirled to form a fuel rich outer ring disposed about an air rich inner portion before the fuel is delivered to the coal nozzle.

A fluidized bed reactor includes a bottom portion, a roof portion, and side walls vertically extending between the bottom portion and the roof portion, forming a reaction chamber of the reactor. At least one side wall of the reaction chamber forms at least one vertical indentation in the reaction chamber, which indentation extends from the plane of the at least one side wall towards the reaction chamber. The indentation extending from the plane of the at least one side wall towards the reaction chamber is formed of a portion of the at least one side wall, protruding from the plane of the at least one side wall towards the reaction chamber, and the portion of the at least one side wall includes at least two substantially vertical indenting wall portions deviating from the plane of the at least one side wall at vertical lines within a distance from each other.

A combustion device in the form of an elevated fixed-grate that includes arcuately shaped solid refractory brick with ribs placed thereunder so as to allow horizontal air flow for fuel combustion. The brick are arranged atop one another in a stacked concentric configuration that forms a central fuel passageway and allows cascading of a fuel pile throughout the combustion stages. The device provides the benefit of proper de-ashing online while distributing the underfire air radially around the fuel pile. The elevated design of the bricks allows the air to be evenly distributed throughout the fuel pile and further allows the isolation of overfire and underfire air. Segregating overfire and underfire air in an evenly distributed manner allows the burner to combust a wide range of fuel moisture contents without modifying the mechanical components of the burner.

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.

A system and techniques for waste oil combustion are provided. The techniques include straining waste oil, separating contaminants from the strained waste oil to produce segregated layers of waste oil, selectively drawing a segregated layer of the waste oil, entraining the drawn waste oil to a burner for combustion, and regulating flow rate to produce a controllable amount of heat output. The system includes a container for straining waste oil, a storage drum for separating contaminants from the strained waste oil via gravity separation to produce segregated waste oil, an oil uptake channel for entraining the waste oil from the storage drum, a fuel regulator for controlling rate of flow of the waste oil from the storage drum to a burner head via the oil uptake channel, and a burner head control for repositioning a burner head under the input stream to produce a controllable amount of heat output.

A hydrogen vacuum furnace (100) is provided with a process chamber (1) wherein a subject (10) to be heated is stored; a heating chamber (2) wherein a heater lamp (25) is stored; and a crystal board (3) for separating the subject (10) and the heater lamp (25) one from the other. In the hydrogen vacuum furnace (100), the subject (10) is heated by a radiant ray applied from the heater lamp (25). The process chamber (1) and the heating chamber (2) are provided with gas feed ports (11, 21) and exhaust ports (12, 22), respectively, for feeding and exhausting a gas. When the subject (10) is being heated, atmospheric pressure in each chamber is adjusted so that the heating chamber (2) is under positive pressure to the process chamber (1) by feeding or exhausting the gas.

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.

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.

The present invention provides a solar-cell-integrated gas production device that can generate a first gas and a second gas by utilizing an electromotive force of a solar cell, and that can supply power to an external circuit by utilizing the same solar cell. The solar-cell-integrated gas production device according to the present invention comprises: a photoelectric conversion part having a light acceptance surface and its back surface; a first electrolysis electrode provided on the back surface of the photoelectric conversion part so as to be capable of being immersed into an electrolytic solution; a second electrolysis electrode provided on the back surface of the photoelectric conversion part so as to be capable of being immersed into the electrolytic solution; and a changeover part, wherein the first electrolysis electrode and the second electrolysis electrode are provided to be capable of electrolyzing the electrolytic solution to generate a first gas and a second gas by utilizing an electromotive force generated by irradiating the photoelectric conversion part with light, and the changeover part makes a changeover between a circuit that outputs the electromotive force, generated by irradiating the photoelectric conversion part outputs the electromotive force, generated by irradiating the photoelectric conversion part with light, to the first electrolysis electrode and the second electrolysis electrode.

This invention is directed to a flexible solar cell photovoltaic module with high light transmittance based on modified substrate, which belongs to the field of thin-film solar cell technology. The objective of the present invention to provide a technical solution for a transparent flexible solar cell module and its fabrication method. Technical features include using a stainless steel template to mold a modified polyimide PI substrate (the PI substrate). The PI substrate has light-passing through-holes, including draining holes and convergence holes, through and distributed on the PI substrate, a conductive film layer, and various stacked photoelectric conversion film layers. The creativeness of the present invention is obvious, such as reducing the short circuit and current leakage due to crystallization of the photoelectric layer interface caused by a subsequent process of laser etching the conductive film layer, reducing the composition on the surface of the solar cell, reducing steps of the fabrication process, and lowering the production cost. Further, the present invention significantly increases the conversion efficiency and load capacity of the solar cell and the quality-cost ratio. The transparent flexible solar cell photovoltaic module also has a broad range of applications.

Accordingly, a method of forming a metal chalcogenide material may comprise introducing at least one metal precursor and at least one chalcogen precursor into a chamber comprising a substrate, the at least one metal precursor comprising an amine or imine compound of an alkali metal, an alkaline earth metal, a transition metal, a post-transition metal, or a metalloid, and the at least one chalcogen precursor comprising a hydride, alkyl, or aryl compound of sulfur, selenium, or tellurium. The at least one metal precursor and the at least one chalcogen precursor may be reacted to form a metal chalcogenide material over the substrate. A method of forming a metal telluride material, a method of forming a semiconductor device structure, and a semiconductor device structure are also described.

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.

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 PV panel uses an array of small silicon sphere diodes (10-300 microns in diameter) connected in parallel. The spheres are embedded in an uncured aluminum-containing layer, and the aluminum-containing layer is heated to anneal the aluminum-containing layer as well as p-dope the bottom surface of the spheres. A phosphorus-containing layer is deposited over the spheres to dope the top surface n-type, forming a pn junction. The phosphorus layer is then removed. A conductor is deposited to contact the top surface. Alternatively, the spheres are deposited with a p-type core and an n-type outer shell. After deposition, the top surface is etched to expose the core. A first conductor layer contacts the bottom surface, and a second conductor layer contacts the exposed core. A liquid lens material is deposited over the rounded top surface of the spheres and cured to provide conformal lenses designed to increase the PV panel efficiency.

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.

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 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 apparatus feeds a metal strip with cutaway portions in a conveying direction and includes: a reference plate on which the metal strip is placed and in which a slit is formed; moving bodies that are provided below the reference plate and are moved by driving means parallel to the reference plate in the conveying direction; feed pins that advance into the cutaway portions, are provided on the moving bodies so as to move up and down with respect to the reference plate, and pull the metal strip in the conveying direction when the moving bodies move; and at least one guide portion that contacts a side surface on an opposite side of the metal strip to the cutaway portions and guides conveyance of the metal strip.

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.

A stock feeder for woodworking equipment includes a base, a cross clamp, a horizontal bar unit, a vertical bar unit, a feeding unit, and an electrical unit. The electrical unit has an electrical unit main body and a variable-frequency drive. The electrical unit main body has a first housing, a plurality of heat dissipation grooves provided on the outer periphery of the first housing, and a power fan which is independently mounted on a top portion of the first housing and in communication with the heat dissipation grooves. The variable-frequency drive has a second housing, a variable-frequency circuit sealed in the second housing, and a control panel exposed outside the second housing. The second housing has an outer surface provided with a plurality of heat dissipation slots corresponding in position to and in communication with the heat dissipation grooves of the electrical unit main body.