bluuebunny/crossref_metadata_2025_split huggingface dataset:
ANALISIS KEJADIAN BENCANA TANAH LONGSOR TANGGAL 12 DESEMBER 2014 DI DUSUN JEMBLUNG, DESA SAMPANG, KECAMATAN KARANGKOBAR, KABUPATEN BANJARNEGARA, PROVINSI JAWA TENGAH
Authors: Naryanto Heru Sri 
Published: May 2019

AbstrakKejadian bencana tanah longsor semakin sering terjadi di Indonesia, termasuk di Kabupaten Banjarnegara. Bencana tanah longsor kembali menimpa warga Dusun Jemblung, Desa Sampang, Kecamatan Karangkobar, Kabupaten Banjarnegara, Provinsi Jawa Tengah pada hari Jumat, 12 Desember 2014 jam 17.30 WIB. Tipologi tanah longsor yang terjadi adalah tipe rotasi, yang kemudian ke arah bawah berkembang menjadi aliran debris akibat material longsoran yang bercampur dengan massa air yang sangat jenuh. Faktor-faktor yang mempengaruhi terjadinya tanah longsor di Banjarnegara 12 Desember 2014 antara lain adalah: geomorfologi terbentuk oleh perbukitan di sedang sampai terjal, batuan penutup berupa soil berasal dari pelapukan batuan breksi vulkanik, terbentuknya rekahan batuan di bagian atas mahkota longsor, curah hujan yang sangat ekstrim, terbentuk mataair pada bagian atas dan tengah bukit, tataguna lahan yang sudah banyak berubah dan aktivitas manusia yang sudah menjarah daerah kritis. Banyak faktor-faktor yang mempengaruhi terjadinya tanah longsor, tetapi dari hasil analisis ada tiga faktor utama penyebab terjadinya tanah longsor yaitu: terjadinya hujan ekstrim (lebat) selama tiga hari berturut-turut sebelum terjadi longsor, topografi pembentuk tanah longsor sangat terjal, tanah (soil) hasil pelapukan batuan sangat tebal dan bersifat menyerap air sehingga mudah jenuh. Berkaitan dengan hal tersebut sangat dibutuhkan berbagai kegiatan pengurangan risiko bencana (PRB) untuk meminimalisasi jumlah korban baik jiwa maupun harta. Kata kunci: Tanah Longsor, Banjarnegara, Topografi Terjal, Soil Tebal, Curah Hujan Ekstrim, Pengurangan Risiko Bencana
Pelatihan Motivasi dan Orientasi Masa Depan Peserta Didik dengan Menggunakan Peta Mimpi
Authors: Khairunnisa Yasmine , Rizkiana Fitria , Apriani Herlina , Prasiska Emilda 
Published: May 2019

Abstrak: Sebagian besar anak-anak di SMAN 1 Kandangan tidak memiliki rencana masa depan yang jelas sesuai dengan keinginan mereka; masa depan mereka ditentukan oleh orang tua ataupun keadaan. Maka dari itu, kegiatan pengabdian kepada masyarakat dilaksanakan dengan tujuan untuk memupuk motivasi siswa-siswi di sekolah melalui pelatihan atau workshop untuk membantu mereka menemukan semangat belajarnya demi meraih cita-cita yang diinginkannya, serta membantu peserta didik yang masih kebingungan untuk memutuskan rencana masa depannya agar mampu secara mandiri merencanakan kehidupannya. Kegiatan ini dilaksanakan dalam bentuk workshop atau pelatihan dengan konsep seminar menggunakan media peta mimpi yang berisikan bagan rencana dari tahun 2018 hingga 2028. Pada kertas tersebut, peserta didik menuliskan secara rinci rencana masa depannya dalam rentang waktu 10 tahun. Kegiatan pengabdian kepada masyarakat di SMAN 1 Kandangan ini berjalan dengan lancar dan mendapat antusiasme yang besar dari siswa. Namun, kurang panjangnya waktu yang disediakan menyebabkan siswa kesulitan untuk mengisi peta mimpinya karena siswa terkesan dituntut untuk tiba-tiba menuliskan rencana masa depan secara detail tanpa diberikan waktu untuk berpikir. Dari hasil angket siswa didapatkan bahwa sebagian besar siswa memiliki minat yang besar untuk belajar dan meneruskan pendidikannya, serta mereka memiliki motivasi yang mendasari semangat mereka untuk belajar yang dipengaruhi oleh orang tua, teman, dan lingkungan sekitarnya. Kata kunci: motivasi; masa depan; peta mimpi
Research and Outcomes at the Truth and Reconciliation Commission
Authors: Miller James R. 
Published: May 2019

Compared to other commissions of inquiry, the Truth and Reconciliation Commission (trc) that investigated residential schools in Canada has had a modest research output and influence on public policy. Although the commissioners worked hard to carry out their mandate and raise awareness of the importance of resolving the legacy of residential schooling and promoting reconciliation, their effectiveness was hampered by several factors. Opposition from some interest groups, including the federal government, complicated their efforts, while some of their own characteristics and approaches also contributed to their difficulties. The limitations imposed by the Indian Residential School Settlement Agreement that defined their assignment, the heavy reliance on legal talent within the commission, and the sheer size of the task they faced were some of the challenges confronting the trc. Ironically, the emphasis of the commission reports on the centrality of history and the commission’s definition of “reconciliation” might prove to be two of the most enduring elements of the trc’s legacy.
Broken Exhaust Valve
Authors: Kallenbach Rudolf , Fichter Rudolf 
Published: May 2019

Abstract
A broken exhaust valve from the cylinder of a motor car had a 30-mm disk diam and 8-mm stem diam. The site of the fracture was directly where the valve cone joined the cylindrical stem. Both the cone and the stem were heavily scaled in the vicinity of the fracture; in some parts the scale has flaked off. Furthermore, the rim of the disk was badly damaged by secondary mechanical action. The core of the valve had a very fine austenitic microstructure with precipitations of numerous granular and very fine, mostly rounded carbides and tine segregation bands. A hard alloy facing was welded on to the valve seat. Fracture was a consequence of fatigue corrosion cracking, itself strongly promoted by the presence of sulphur compounds. The origin of these corrosive sulphur compounds could not be explained.
Contact Fatigue Failure of an Axle Shaft Spur Pinion
Authors: Alban Lester E. 
Published: May 2019

Abstract
One end of an axle shaft containing the integral spur pinion was submitted for examination, along with the report of a tooth pitting failure. The spur pinion, integral to the axle shaft, operated in a medium-size, off-highway truck at an open-pit mine, for “a relatively short time.” Only the pinion head had been returned. The shaft portion had been torch-cut away. Chemical analysis along with the microstructure confirmed the specified material was SAE 43BV12 Ni-Cr-Mo alloy steel. The mode of failure was surface contact fatigue through the shear plane subsurface at the lowest point of single-tooth contact. The cause of failure was tooth-tip interference from the mating gear teeth. Because the mating parts within the assembly had not been returned or examined, unanswered questions remained.
Thermal Analyses of a Polymer Failure
Authors: Kusy Robert P. , Whitley John Q. 
Published: May 2019

Abstract
Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to analyze an automotive polyoxymethylene (POM) sensor housing that was depolymerizing during service. It was found that a combination of heat, oxygen, and sulfuric acid attacked and caused premature failure of the part. POM should not be selected for automotive applications where elevated temperatures and acidic environments can exist. If exposure to acid is suspected, sodium bicarbonate should be applied to neutralize the surrounding environment, followed by copious quantities of water, and repeated until no effervescence is observed.
Creep Rupture in a Superheated Steam Transfer Line
Authors: da Silveira T.L. , Le May I. 
Published: May 2019

Abstract
Rupture occurred at a bend in a superheated steam transfer line between a header and a desuperheater of a boiler producing 230 t/h of steam at 540 deg C and 118 kPa. The boiler had operated for 77,000 h. Rupture occurred along the outer bend radius of the 168 mm diam tube, this being of 1 Cr, 0.5 Mo steel with a wall thickness of 14 mm. The design temperature of this tube was 490 deg C, but there is evidence that it was operating at a temperature much above 500 deg C. Metallographic analysis disclosed an advanced stage of creep damage accumulation in the form of local cracks, microcracks, and aligned damage centers which showed up as voids upon repeated polish-etch cycles. Because of the local nature of creep damage that can occur, any inspection that involves in situ metallography must be conducted at exactly the right or critical position or the presence of damage may not be detected.
Failure Analysis of a Large Centrifugal Blower
Authors: Tait R.B. , Garrett G.G. , Spencer D.P. 
Published: May 2019

Abstract
A fracture mechanics based failure analysis and life prediction of a large centrifugal fan made from low-carbon, medium-strength steel was undertaken following shortcomings in attempts to explain its fatigue life from start stop cycles alone. Measurements of the fracture toughness and flaw size at failure, coupled with quantitative SEM fractography using striation spacing methods, revealed that the cyclic stress amplitudes just prior to failure were much larger than expected, in this particular case. Subsequent improvements in fan design and fabrication have effectively alleviated the problem of slow, high cycle fatigue crack growth, at normal operating stresses in similar fans.
Turbine Blade Failures, Who Pays?
Authors: Missimer Jack R. 
Published: May 2019

Abstract
The assignment of financial liability for turbine blade failures in steam turbines rests on the ability to determine the damage mechanism or mechanisms responsible for the failure. A discussion is presented outlining various items to look for in a post-turbine blade failure investigation. The discussion centers around the question of how to determine whether the failure was a fatigue induced failure, occurring in accordance with normal life cycle estimates, or whether outside influences could have initiated or hastened the failure.
Failure Analysis of Brass Tubes
Authors: Lawrence Samuel J. , Bodnar Richard L. 
Published: May 2019

Abstract
Admiralty brass (Alloy C44300) cooling tubes which were part of a heat exchanger in a turbogenerator that provided electricity to a manufacturing plant failed. A mixture of non-recirculating city and “spring pit” water flowed through bundles of tubes to cool the oil in which they are immersed. However, a problem developed when several of the brass tubes cracked transversely, allowing cooling water to mix with the oil. The presence of a tensile stress, intergranular cracks, and a corrosion product suggested the tube failures resulted from stress-corrosion cracking. The main corrosion product was cupric hydroxychloride. In addition to switching to a more corrosion-resistant alloy, extreme care should be taken in the manufacturing of the replacement tube bundles to avoid imparting any residual tensile stresses in the tubing. Analyses of city and spring-pit water were recommended also, to determine which contained the least-harmful corrosive chemicals.
Recovery of a Type 304 Stainless Steel Piping System Contaminated with Chlorides
Authors: Stein A. A. , Zilberstein V. , Clancy W. S. , Davis G. J. 
Published: May 2019

Abstract
One inch diam Type 304 stainless steel piping was designed to carry containment atmosphere samples to an analyzer to monitor hydrogen and oxygen levels during operational and the design basis accident conditions that are postulated to occur in a boiling water reactor. Only one of six lines in the system had thru-wall cracks. Shallow incipient cracks were detected at the lowest elevations of one other line. The balance of the system had no signs of SCC attack. Chlorides and corrosion deposits in varying amounts were found throughout the system. The failure mechanism was transgranular, chloride, stress-corrosion cracking. Replacement decisions were based on the presence of SCC attack or heavy corrosion deposits indicative of extended exposure time to chloride-contaminated water. The existing uncracked pipe, about 75 percent of the piping in the system, was retained despite the presence of low level surface chlorides. Controls were implemented to insure that temperatures are kept below 150 deg F, or, walls of the pipe are moisture-free or the cumulative wetted period will never exceed 30 h.
Investigation of Intergranular Stress Corrosion Cracking in the Fuel Pool at Three Mile Island Unit 1
Authors: Czajkowski Carl J. 
Published: May 2019

Abstract
An intergranular stress-corrosion cracking failure of 304 stainless steel pipe in 2000 ppm B as H3BO3 + H2O at 100 deg C was investigated. Constant extension rate testing produced an intergranular type failure in material in air. Chemical analysis was performed on both the base metal and weld material, in addition to fractography, EPR testing and optical microscopy in discerning the mode of failure. Various effects of Cl-, O2 and MnS are discussed. Results indicated that the cause of failure was the severe sensitization coupled with probable contamination by S and possibly by Cl ions.
Thermal Exposure Assessment by Quantitative Microscopy and Selective Etching
Authors: Vander Voort George F. 
Published: May 2019

Abstract
The accident at Three Mile Island Unit No. 2 on 28 March 1979 was the worst nuclear accident in US history. By Jan 1990, it was possible to electrochemically machine coupons from the lower head using a specially designed tool. The specimens contained the ER308L stainless steel cladding and the A533 Grade B plate material to a depth of about mid-wall. The microstructures of these specimens were compared to that of specimens cut from the Midland, Michigan reactor vessel, made from the same grade and thickness but never placed in service. These specimens were subjected to known thermal treatments between 800 and 1100 deg C for periods of 1 to 100 min. Microstructural parameters in the control specimens and in those from TMI-2 were quantified. Selective etchants were used to better discriminate desired microstructural features, particularly in the cladding. This report is a progress report on the quantification of changes in both the degree of carbide precipitation and delta ferrite content and shape in the cladding as a function of temperature and time to refine the estimates of the maximum temperatures experienced.
Alloy 430 Ferritic Stainless Steel Welds Fail due to Stress-Corrosion Cracking in Heat-Recovery Steam Generator
Authors: Krafft H. 
Published: May 2019

Abstract
Alloy 430 stainless steel tube-to-header welds failed in a heat recovery steam generator (HRSG) within one year of commissioning. The HRSG was in a combined cycle, gas-fired, combustion turbine electric power plant. Alloy 430, a 17% Cr ferritic stainless steel, was selected because of its resistance to chloride and sulfuric acid dewpoint corrosion under conditions potentially present in the HRSG low-pressure feedwater economizer. Intergranular corrosion and cracking were found in the weld metal and heat-affected zones. The hardness in these regions was up to 35 HRC, and the weld had received a postweld heat treatment (PWHT). Metallographic examination revealed that the corroded areas contained undertempered martensite. Fully tempered weld areas with a hardness of 93 HRB were not attacked. No evidence of corrosion fatigue was found. Uneven temperature control during PWHT was the most likely cause of failure.
Investigation of Turbine Disc Cracking by Field Metallography
Authors: Cervoni A. , Clark M. A. 
Published: May 2019

Abstract
Stress-corrosion cracking of low-alloy steel turbine discs has emerged as a generic concern in nuclear generating stations. An investigation that made extensive use of field metallographic techniques to examine suspected cracking in such a component is described. The crack position, and its relationship to surface topographic features, were examined and recorded by magnetic rubber and high-resolution dental rubber replicating materials. Corrosion deposits on keyway surfaces and within the crack were collected with acetate foil replicas applied and then stripped from the keyway surfaces. Microstructural details were revealed by the use of field metallographic preparation techniques and replicated by acetate foil for examination with optical and scanning electron microscopes. It was possible by these techniques to establish the cracking mechanism as stress corrosion possibly related to chloride or sulphate ion steam contaminants. Subsequent sectioning and conventional metallography confirmed both the validity of the conclusions and the replication techniques.
Corrosion of Copper Cooling-Water Tubing in a Heat Exchanger
Authors: Khan A.H. 
Published: May 2019

Abstract
A straight-tube cooler type heat exchanger had been in service for about ten years serving a coal pulverizer in Georgia. Non-potable cooling water from a local lake passed through the inner surfaces of the copper tubing and was cooling the hot oil that surrounded the outer diametral surfaces. Several of the heat exchangers used in the same application at the plant had experienced a severe reduction in efficiency in the past few years. One heat exchanger reportedly experienced some form of leakage following discovery of oil contaminating the cooling water. This heat exchanger was the subject of a failure investigation to determine the cause and location of the leaks. Corrosion products primarily contained copper oxide, as would be expected from a copper tubing. The product also exhibited the presence of a significant amount of iron oxides. Metallographic cross sectioning of the tubes and microscopic analysis revealed several large and small well rounded corrosion pits present at the inner diametral surfaces. The cause of corrosion was attributed to corrosive waters that were not only corroding the copper, but were corroding steel pipes upstream from the tubing.
Failure Analysis of Boiler Water Wall-Tubes at a Power Generation Plant
Authors: El-Batahgy A. , Metwally W. 
Published: May 2019

Abstract
Several waterwall tubes in a power station boiler failed after ten years of service. The boiler is a suspension type equipped with 30 IK boxes where retractable soot blowers are inserted to clean the inside of the boiler using high-pressure steam. The tubes, which operate at 693 deg F (367 deg C) and 2935 psi (20.5 MPa), failed near the IK boxes as a result of thermal fatigue. Thermal fatigue damage was accelerated by repetitive exposure to water droplets from the soot blower and the associated rapid cooling.
Damage in a Gas Turbine Hot Gas Casing
Authors: da Silveira T.L. , Le May I. 
Published: May 2019

Abstract
The hot gas casing of a gas turbine used for peak load power production had developed extensive cracking during operation. The operating time was 18,000 h, and it had been subjected to 1,600 operating cycles. The gas temperature on the hot side was 985 deg C, on the cold side 204 deg C, the material being AISI 321 stainless steel. The purpose of the present study was to determine optimum repair welding procedures on the premise that the material was basically sound and undamaged by creep. The cracking was the result of thermal fatigue, and such cracks can propagate at elevated temperature, with damage ahead of the crack tip occurring by means of very local processes of creep. Metallographic examination disclosed heavy surface layers of carbides, such that the material was extremely brittle when subjected to bending. Accordingly, although it was demonstrated that the casing could be welded successfully, it was suggested that the remaining useful life was effectively exhausted and that it should be replaced. Thermal stresses produced during operation would rapidly result in additional cracks.
Low Cycle Thermal Fatigue and Fracture of Reinforced Piping
Authors: O'Donnell W.J. , Watson J.M. , Mallin W.B. , Kenrick J.R. 
Published: May 2019

Abstract
A large diameter steel pipe reinforced by stiffening rings with saddle supports was subjected to thermal cycling as the system was started up, operated, and shut down. The pipe functioned as an emission control exhaust duct from a furnace and was designed originally using lengths of rolled and welded COR-TEN steel plate butt welded together on site. The pipe sustained local buckling and cracking, then fractured during the first five months of operation. Failure was due to low cycle fatigue and fast fracture caused by differential thermal expansion stresses. Thermal lag between the stiffening rings welded to the outside of the pipe and the pipe wall itself resulted in large radial and axial thermal stresses at the welds. Redundant tied down saddle supports in each segment of pipe between expansion joints restrained pipe arching due to circumferential temperature variations, producing large axial thermal bending stresses. Thermal cycling of the system initiated fatigue cracks at the stiffener rings. When the critical crack size was reached, fast fracture occurred. The system was redesigned by eliminating the redundant restraints and by modifying the stiffener rings to permit free radial thermal breathing of the pipe.
Broken Rim of a Rolling Mill Transmission
Authors: Naumann Friedrich Karl , Spies Ferdinand 
Published: May 2019

Abstract
The rim of a gear wheel of 420 mm width and 3100 mm in diam broke after four years of operation time in a sheet bar three-high rolling mill. The rim was forged from steel with about 0.4C, 0.8Si and 1.1Mn. The rim started to break in the tooth bottom from a fatigue fracture which extended from the gear side to more than half the rim width. A second incipient failure commenced from the opposite tooth bottom. Both fractures joined below the tooth of the rim. Both incipient cracks were fatigue fractures with several starting points, all located in the transition between tooth flank and tooth bottom. The remaining failure was a fine-grained ductile fracture. It was found that the teeth were not supported uniformly over the entire width and were thus overloaded on one side. The transition from the tooth flanks to the tooth bottom was sharp-edged, causing a tension peak there. The tooth bottom was machined only roughly. Also, the yield point was a little bit too low.
Oxidized Recuperator Pipes
Authors: Naumann Friedrich Karl , Spies Ferdinand 
Published: May 2019

Abstract
High-chromium steel pipes 42.25 x 3.25 mm from a blast furnace gas fired recuperator for the preheating of air were heavily oxidized and perforated in places. It was found that the blast furnace gas had a high sulfur content. Both the carburization and the formation of sulfide proved that in addition, from time to time at least, combustion was incomplete and the operation was carried out in a reducing atmosphere, with the result that oxygen deficiency prevented the formation or maintenance of a protective surface layer on the external surface of the pipes. The sulfur would probably not have damaged the nickel-free steel used here at the given temperatures if it had been present as sulfur dioxide in an oxidizing atmosphere. The damage was therefore caused primarily by an incorrectly conducted combustion process.
Scaling of Resistance Heating Elements in a Through-Type Annealing Furnace
Authors: Naumann Friedrich Karl , Spies Ferdinand 
Published: May 2019

Abstract
Heating elements, consisting of strips, 40 mm x 2 mm, of the widely used 80Ni-20Cr resistance heating alloy, and designed to withstand a temperature of 1175 deg C, were rendered unusable by scaling after a few months service in a through-type annealing furnace, Although the temperature supposedly did not exceed 1050 deg C. Structural observations indicated a special case of internal oxidation. The required conditions for this were apparently provided by the moist hydrogen atmosphere of the annealing furnace, in which the chromium was oxidized, while the oxides of iron and nickel were reduced. Even the carbon suffered incomplete combustion and was enriched in the core. Thus, no protective layer could form or be maintained. The intergranular advancement of the oxidation may have been favored by the precipitation of chromium-rich carbides on the austenite grain boundaries. This form of internal oxidation is, in the case of Ni-Cr alloys, known as green rot. Alloys containing iron should be more resistant. As a preventive measure it was recommended to reduce the operating temperature of the strip sufficiently to allow the use of Fe-Ni-Cr alloys.