The invention provides a heater arrangement and method for heating a liquid, wherein the heater comprises a heating element, wherein the method comprises (i) heating the liquid in the heater wherein the heating element is in contact with the liquid, and (ii) applying a potential difference between the heating element and a counter electrode, wherein the potential difference has an AC component whereby the potential difference varies with an AC frequency in the range of 0.01-100 Hz and wherein the potential difference is applied with a cycle time, wherein the potential difference has a sign during a first part of the cycle time that is opposite of the sign of the potential difference during a second part of the cycle time, and wherein during one or more of the first part of the cycle time and the second part of the cycle time, the potential difference temporarily changes sign.

A heater comprising: an outer tube having a first thermal expansion coefficient; an inner tube having a second thermal expansion coefficient that is less than the first thermal expansion coefficient, wherein the inner tube is disposed concentrically with the outer tube such that there is a space between the inner and outer tubes; a conductive powder disposed within the space between the inner and outer tubes; and two electrodes in electrical contact with the conductive powder such that when a potential is introduced between the electrodes, the conductive powder functions as a resistive heater whose resistance changes with temperature based on different degrees of thermal expansion of the inner and outer tubes.

A heater comprising: an outer tube having a first thermal expansion coefficient; an inner tube having a second thermal expansion coefficient that is less than the first thermal expansion coefficient, wherein the inner tube is disposed concentrically with the outer tube such that there is a space between the inner and outer tubes; a conductive powder disposed within the space between the inner and outer tubes; and two electrodes in electrical contact with the conductive powder such that when a potential is introduced between the electrodes, the conductive powder functions as a resistive heater whose resistance changes with temperature based on different degrees of thermal expansion of the inner and outer tubes.

A system may include a current source; a first metal or alloy component with a first major surface electrically coupled to the current source; a second metal or alloy component with a second major surface electrically coupled in series to the first component and the current source via an external electrical conductor, where the first and second major surfaces are positioned adjacent to each other to define a joint region; a metal or alloy powder disposed in at least a portion of the joint region; and a controller. The controller may be configured to cause the current source to output an alternating current that conducts through the first component and the second component to induce magnetic eddy currents, magnetic hysteresis, or both within at least a portion of the metal or alloy powder disposed in at least the first portion of the joint region.

A system may include a current source; a first metal or alloy component with a first major surface electrically coupled to the current source; a second metal or alloy component with a second major surface electrically coupled in series to the first component and the current source via an external electrical conductor, where the first and second major surfaces are positioned adjacent to each other to define a joint region; a metal or alloy powder disposed in at least a portion of the joint region; and a controller. The controller may be configured to cause the current source to output an alternating current that conducts through the first component and the second component to induce magnetic eddy currents, magnetic hysteresis, or both within at least a portion of the metal or alloy powder disposed in at least the first portion of the joint region.

An electrode water heater/steam generator is provided. The electrode water heater/steam generator comprises a housing for containing water therein. The housing has at least an opening for transmission of water therethrough. At least two electrodes are disposed inside the housing and secured thereto such that at least one of the electrodes is enabled to vibrate during provision of AC electrical power. Electrical circuitry connects at least one of the electrodes to a live wire of an AC electrical power supply and at least another of the electrodes to a neutral wire of the AC electrical power supply.

An apparatus for casting metals by a nucleated casting technique to create a preform, the apparatus including a mold having a base and a side wall where the base can be moved relative to the side wall to withdraw the preform as it is being created. In various circumstances, portions of a droplet spray created by an atomizing nozzle, i.e., overspray, may accumulate on a top surface of the side wall and prevent or inhibit the preform from being moved relative to the side wall. The atomizing nozzle can be oriented such that the droplet spray passes over the top of the side wall to remelt and remove at least a portion of the overspray that has accumulated thereon. The mold can be rotated such that the overspray formed on a region of or on the entire perimeter of the top surface can pass through the droplet spray and can be removed from the side wall.

A system may include a current source; a first metal or alloy component with a first major surface electrically coupled to the current source; a second metal or alloy component with a second major surface electrically coupled to the current source; a metal or alloy powder disposed in at least a portion of the joint region; and a controller. The first and second major surfaces may be positioned adjacent to each other to define a joint region. The controller may be configured to cause the current source to output an alternating current that passes from the first component, through at least a portion of the metal or alloy powder, into the second component. The frequency of the alternating current may be configured to cause standing electromagnetic waves within at least a portion of the particles of the metal or alloy powder.

A system may include a current source; a first metal or alloy component with a first major surface electrically coupled to the current source; a second metal or alloy component with a second major surface electrically coupled to the current source; a metal or alloy powder disposed in at least a portion of the joint region; and a controller. The first and second major surfaces may be positioned adjacent to each other to define a joint region. The controller may be configured to cause the current source to output an alternating current that passes from the first component, through at least a portion of the metal or alloy powder, into the second component. The frequency of the alternating current may be configured to cause standing electromagnetic waves within at least a portion of the particles of the metal or alloy powder.

A system may include a current source; a first metal or alloy component with a first major surface electrically coupled to the current source; a second metal or alloy component with a second major surface electrically coupled in series to the first component and the current source via an external electrical conductor, where the first and second major surfaces are positioned adjacent to each other to define a joint region; a metal or alloy powder disposed in at least a portion of the joint region; and a controller. The controller may be configured to cause the current source to output an alternating current that conducts through the first component and the second component to induce magnetic eddy currents, magnetic hysteresis, or both within at least a portion of the metal or alloy powder disposed in at least the first portion of the joint region.