Abstract: A tack welding method and a tack welding apparatus that can improve the strength of a tack-welded joint portion and reduce the height of a reinforcement bead is provided. A tack welding method of the present embodiment is a tack welding method of tack-welding a part of a joint portion of a first joint and a second joint at a predetermined interval before main welding. In the tack welding method, a filler metal is supplied to the joint portion, laser light is deflected and irradiated to the joint portion, and the filler metal is cut with the laser light to be welded to the joint portion.

Abstract: A hybrid welding method and a hybrid welding apparatus that can perform welding without dropping a weld metal even in a case of butt-welding in which a gap is present between base materials is provided. A hybrid welding apparatus according to the present invention is a hybrid welding apparatus that butt-welds a first joint and a second joint using laser welding and arc welding, and includes a laser welding device that includes a laser head that irradiates laser light to a welded portion and an arc welding device that includes a welding torch that supplies a filler metal to the welded portion. It is configured such that the laser head is capable of performing horizontal welding and disposed on an upstream side in a welding direction, the welding torch is capable of performing horizontal welding and disposed on a downstream side in the welding direction, and horizontal welding is performed with the first joint and the second joint disposed vertically so as to obtain a substantially horizontal weld line.

Abstract: A tack welding method and a tack welding apparatus that can improve the strength of a tack-welded joint portion and reduce the height of a reinforcement bead is provided. A tack welding method of the present embodiment is a tack welding method of tack-welding a part of a joint portion of a first joint and a second joint at a predetermined interval before main welding. In the tack welding method, a filler metal is supplied to the joint portion, laser light is deflected and irradiated to the joint portion, and the filler metal is cut with the laser light to be welded to the joint portion.

Abstract: The object of the present invention is to achieve excellent reforming ability even at lower temperatures, with a dimethyl ether steam reforming catalyst. According to the present invention, there is provided a dimethyl ether steam reforming catalyst capable of steam-reforming dimethyl ether to obtain hydrogen, comprising active alumina, Cu, and at least one element selected from the group consisting of Mn and Fe, the catalyst being prepared by a sol-gel method, and the catalyst having a porous structure.

Abstract: An object of the present invention is to provide a construction for exhaust emission control, which can prevent thermal deterioration in a catalyst and can heat exhaust gas to a catalyst activation temperature. In the present invention, an electrically heated catalyst portion 10 is provided in a separator 12a in a silencer 3 located at a distance from an engine. This electrically heated catalyst portion 10 heats low-temperature exhaust gas to a catalyst activation temperature. The exhaust pipe 11a branches into three pipes 22a, 22b and 22c in the silencer 3. The electrically heated catalyst portion 10 has a shape surrounding the each outer peripheral surface of pipe 22a, 22b and 22c of an exhaust pipe 11a. Exhaust gas is warmed to a temperature close to the catalyst activation temperature when it flows in the pipes 22a, 22b and 22c, and flows out of the pipe 22a, 22b and 22c.

Abstract: An object of the present invention is to provide an exhaust gas purification catalyst which can minimize the separation of the catalyst layer due to heat and vibration, can suppress thermal deterioration of the catalytic substance, and can exhibit excellent purification capabilities under severe conditions. Specifically, the present invention relates to an exhaust gas purification catalyst wherein an undercoat layer comprising a heat-resistant inorganic oxide having an oxygen-absorbing substance added thereto is formed on a surface of a metallic carrier, and a catalyst-carrying layer is formed on the undercoat layer.

Abstract: The object of the present invention is to achieve excellent reforming ability even at lower temperatures, with a dimethyl ether steam reforming catalyst.

Abstract: An object of the present invention is to provide a construction for exhaust emission control, which can prevent thermal deterioration in a catalyst and can heat exhaust gas to a catalyst activation temperature. In the present invention, an electrically heated catalyst portion 10 is provided in a separator 12a in a silencer 3 located at a distance from an engine. This electrically heated catalyst portion 10 heats low-temperature exhaust gas to a catalyst activation temperature. The exhaust pipe 11a branches into three pipes 22a, 22b and 22c in the silencer 3. The electrically heated catalyst portion 10 has a shape surrounding the each outer peripheral surface of pipe 22a, 22b and 22c of an exhaust pipe 11a. Exhaust gas is warmed to a temperature close to the catalyst activation temperature when it flows in the pipes 22a, 22b and 22c, and flows out of the pipe 22a, 22b and 22c.

Abstract: A compact, highly efficient methanol reforming apparatus is provided in which a CO concentration in a reformed gas can be decreased during load fluctuations below the concentration allowable for fuel cells. A reforming device of the methanol reforming apparatus is formed from a stacked structure of flat sheets. The reforming device includes evaporation and preheating sections for evaporating and preheating the reforming fuel and a reforming section provided with a combustion catalyst accelerating the reaction of reforming fuel which is methanol. Further, an oxidation section for oxidizing CO as a byproduct generated in the reforming section is provided downstream of the reforming section. A sensor is provided in the oxidation section, and air for CO oxidation section cooling is appropriately supplied thereto.

Abstract: A lightweight magnesia clinker containing magnesium oxide in an amount of more than 85 wt. % and having an apparent porosity of more than 40 vol. % and a bulk specific gravity of less than 2.0 g/cm.sup.3 is disclosed. In the lightweight magnesia clinker, the amount of magnesia clinker particles having a particle diameter of smaller than 3 mm is more than 90 wt. % of the amount of all magnesia clinker particles, and the amount of pores formed in the magnesia clicker particles having a pore size of smaller than 50 .mu.m is more than 90 vol. % of the amount of all pores. A process for the preparation of said lightweight magnesia clinker is also disclosed.

Abstract: A magnesia-calcia clinker having a high density, said clinker containing MgO, CaO and Fe.sub.2 O.sub.3 as oxides, having the following chemical composition in percent by weightMgO, CaO and Fe.sub.2 O.sub.3 : at least 99% in totalMgO: at least 10%Fe.sub.2 O.sub.3 : 0.2-5%and having a density corresponding to at least 97.5% of the theoretical density. The above magnesia-calcia clinker can be produced by adding a water-soluble iron compound to sea water, bittern or brine, simultaneously with, or after, the addition of the water-soluble iron compound, adding a calcined product of dolomite, lime or a hydrate thereof to form a precipitate composed mainly of magnesium hydroxide, mixing the resulting magnesium hydroxide with a calcium compound, and dead-burning the resulting mixture.

Abstract: High density magnesia clinker characterized by having a chemical composition, as oxides in weight %, ofMgO: 97.5% or moreCaO: 0.8-2.0%SiO.sub.2 : 0.12-1.0%Fe.sub.2 O.sub.3 : 0.3% or lessAl.sub.2 O.sub.3 : 0.15% or lessB.sub.2 O.sub.3 : 0.03% or lesswith a bulk density of at least 3.48 g/cm.sup.3. The said high density magnesia clinker can be produced by forming magnesium oxide by calcination of naturally occurring magnesite having a composition, based on ignition in weight %,MgO: 97.5% or moreCaO: 0.8-2.0%SiO.sub.2 : traces to 0.15%Fe.sub.2 O.sub.3 : 0.3% or lessAl.sub.2 O.sub.3 : 0.15% or lessB.sub.2 O.sub.3 : 0.1% or less,grinding the same after, or with, addition of amorphous silica, silica gel or a silicon compound capable of forming SiO.sub.2 by dead-burning in such a manner as to have the SiO.sub.2 content of 0.12-1.0% after dead-burning and dead-burning.