bluuebunny/crossref_metadata_2025 huggingface dataset:
Peran Pemerintah Desa Panggungharjo Bantul Dalam Mewujudkan Good Governance Melalui Pengembangan Sistem Informasi Desa
Authors: Suryani Dewi Amanatun
Published: May 2019

Abstrak

 

Implementasi Undang-Undang Desa secara umum memberikan kesempatan kepada desa untuk melakukan demokratisasi proses kebijakan, konsolidasi sumber daya dan aset, dan penguatan dan pemberdayaan masyarakat dengan memunculkan partisipasi dari masyarakat. Penelitian ini bertujuan untuk mendeskripsikan peran Pemerintah desa dalam mewujudkan  penyelenggaraan tata pemerintahan yang baik, transparan dan akuntabel melalui pengembangan sistem informasi desa. Metode penelitian yang dilakukan penulis menggunakan jenis penelitian deskriptif dengan pendekatan kualitatif. Teknik pengumpulan data dengan observasi, wawancara dan dokumentasi. Berdasarkan hasil penelitian yang telah dilakukan dapat disimpulkan bahwa Desa Panggungharjo Kecamatan Sewon Bantul telah menerapkan keterbukaan informasi yang memberikan kesempatan kepada masyarakat untuk mengakses informasi publik desa. Pemerintah Desa mempunyai komitmen untuk mengembangkan sistem informasi desa melalui penyediaan website yang memuat profil desa, program kegiatan, dan laporan penggunaan anggaran. Dalam mewujudkan good goverment, desa Panggungharjo masih memiliki kendala diantaranya keterbatasan sumber daya manusia dalam memahami peraturan perundang-undangan tentang keterbukaan informasi publik dan pengelolaan sistem informasi desa, metode kerja yang implementatif dan teruji, prosedur layanan informasi publik, penyediaan informasi publik sesuai kebutuhan, dan sebagian masyarakat kurang berpartisipasi aktif dalam proses pengambilan kebijakan maupun pengawasan penyelengaraan pemerintahan.

 

Kata Kunci : Peran Pemerintah Desa; Good Governance; Sistem Informasi Desa.
Prikaz kretanja izbjeglica preko teritorija Republike Hrvatske u dnevnom tisku (Večernji list, Jutarnji list, 24 sata)
Authors: Peran Suzana , Raguž Anđelka
Published: May 2019

Cilj je ovoga rada istražiti koliko su i kako hrvatske dnevne novine – Jutarnji list, Večernji list i 24sata – izvještavale o izbjegličkome valu i prolasku izbjeglica kroz Republiku Hrvatsku od rujna 2015. do travnja 2017. godine. Istraživali smo i način izvještavanja kroz prisutnost novinarskog stava, možebitno etiketiranje izbjeglica, kao i kršenje etičnih normi u izvještavanju. Pozornost je posebno posvećena odnosu naslova i teksta objava. U provedenom kvantitativnom istraživanju, s jedne su strane odbačene početne pretpostavke da izvještavanje o izbjeglicama uključuje senzacionalistički pristup temi, da se izbjeglice i (e)migrante medijski prikazuje kao opasne za gospodarsku stabilnost zemlje i kao potencijalnu terorističku prijetnju te da istodobno novinski prilozi apeliraju na emocije čitatelja. S druge je strane istraživanje potvrdilo kako se medijski djelatnici pri izvještavanju o izbjeglicama nisu pridržavali temeljnih novinarskih postulata koji od njih zahtijevaju nepristranost, pozivanje na više izvora i zaštitu identiteta djece i mlađih maloljetnika. U završnom dijelu radu donosimo rezultate i analizu empirijskog istraživanja, a u zaključku ukazujemo na važnost stavljanja dobivenih rezultata u suodnos s novim istraživanjima, posebno onima koji bi bili usmjereni na objave na društvenim mrežama i na lažne vijesti koje se njima šire o izbjegličkoj i migrantskoj problematici.
Formativno-katehetski pristup pojmu ljepote
Authors: Sando Dragomir
Published: May 2019

Značajno svojstvo pedagogije jest ljepota. Ona u širem smislu označava sve ono što potječe od estetskoga, ali i egzistencijalnoga. Njezini korijeni su još od vremena i načina stvaranja i poretka postojanja svijeta, ali i njegova krajnjeg smisla, a samim tim i odgojno-obrazovnog ustrojstva u svijetu. Ljepota tako postaje svojstvo kozmoloških, antropoloških, teoloških, eklezioloških, socioloških i drugih odlika svijeta. Čovjek je stvoren kao lijepo biće, kao savršeno lijepo, ali nedovršeno biće, i kao takav je nositelj mogućnosti vječnog života, stvaran za lučonošu primatelja božanske svjetlosti i ljepote. Čovjek kao slika Božja i jest stvoren s namjerom da bude savršeno lijep i prosvijetljen jer je »slovjesan«, suobličen Bogu, jer je bogolik i stvoren za nešto mnogo uzvišenije i neusporedivo vrjednije od svega što postoji.
تعلمية اللغة العربية وتعليمها في البحرين
Authors: lahbacha saber
Published: May 2019

هذا الفصل يتناول واقع تعليم اللغة العربية في مملكة البحرين
Konsep Dasar Administrasi dan Supervisi Pendidikan
Authors: fitriyenti
Published: May 2019

KONSEP DASAR ADMINISTRASI PENDIDIKANA.Pengertian administrasiAda dua pengertian administrasi yaitu dalam arti sempit dan arti luas :1.Administrasi dalam ari sempitKegiatan penyusunan dan pencatatandata dan informasi secara sistematis dengan tujuan untuk menyediakan keterangan serta memudahakan memperolehnya kembali secara keseluruhan dan dalam suatu hubungan satu sama lain. Administrasi dalam arti sempit ini lebih tepat disebut tata usaha.2.Administrasi dalam arti luasKegiatan kerjasama yang dilakukan sekelompok orang berdasarkan pembagian kerja sebagaimana ditentukan dalam struktur dengan mendayagunakan sumber daya untuk mencapai tujuan secara efektif dan efisien. Jadi pengertian administrasi dalam arti luas adalah memiliki unsur-unsur sekelompok orang, kerja sama, pembagian tugas secara terstruktur, kegiatan yang runtut dalam proses, tujuan yang akan dicapai, dan pemanfaatan berbagai sumber.Intinya, administrasi melingkupi seluruh kegiatan, dari pengaturan hingga pengurusan sekelompok orang yeng memiliki diferensiasi pekerjaan untuk mencapai suatu tujuan bersama.
Women Empowerment in Tourism: Special Reference to Pokhara Metropolitan City
Authors: Palikhe Amin
Published: May 2019

This article examines women empowerment in tourism with reference to the Pokhara Metropolitan City, Nepal. The major objective is to identify the women in tourism, their situation, problem, and obstacle and future perspective in the tourism industry. The descriptive and analytical research design is used. Primary and secondary sources of data are used. Fifty-two samples have been taken from the tourism industry (hotel, lodge, travel, and trekking) and a questionnaire distributed to women. Some women are entrepreneurs and some are employees in the tourism field in Pokhara. Women are gradually being motivated to involve themselves in tourism-related business. These days, women’s contribution does not equate males when they are compared. Most of the women work at a lower level and they are satisfied with their work and their contribution. Women face different obstacles that hamper them to move, initiate and run their business. Women have better potentiality in different tourism sectors like direct and indirect, such as framing, planting, travel, and trekking, rural tourism, home stay, medication, and hospitability. But they have various causes and reasons to work at a lower level.
Impact of Micro-Finance Intervention on Livelihood Status of Women Households
Authors: Chapagain Ramkrishna , Sapkota Pradeep , Gautam Mukta Raj
Published: May 2019

This study attempts to examine the impact of micro finance intervention on the livelihood status of the women households. With the purpose of measuring the impact of micro-finance, 60 non-intervened and the rest 60 intervened respondents having minimum five years attachment with Chhimek Laghubitta Bittiya Sanstha Limited established in the rural area of Pokhara Metropolitan City and nearby VDCs has been selected. Primary data were collected by a semi-structured questionnaire, and both qualitative and quantitative data were used to assess the impact of micro-finance intervention. The study is based on the interventional research design and used randomized control trial approach. Respondents were selected through stratified random sampling. The collected data were analyzed by using parametric (t-test) and non-parametric (Chi-square test) test. The findings of the research show that micro-finance intervention has positive impact on income level, consumption expenses, capital expenditure and savings. The research also shows that micro-finance intervention has positive association with occupational status and micro enterprise creation. One sample t-test on respondent’s rating indicates that micro finance has reached to the remote areas, enhances financial inclusion, facilitates to poverty reduction and ultimately increases the livelihood status of women of rural areas of Pokhara Metropolitan City and nearby VDCs.
Tax Payers’ Knowledge Towards Value Added Tax in Nepal
Authors: Gnawali Achyut
Published: May 2019

Value added tax (VAT) has been the most essential choice as an ingredient of tax reforms of developing countries like Nepal, which leads to revenue enhancement and sustainable economic development. As VAT was a new concept in Nepal, a comprehensive taxpayer education program was launched to impart knowledge regarding the various aspects of VAT to parliamentarians, industrialists, businesspersons, consumers as well as various sections of the society. The study used descriptive and survey research design. Data were collected through questionnaires. Statistical tools were used to make a proper analysis. It is found that more than 88 percent of respondents are aware enough to ask tax invoice after purchasing goods or services. Most of them ask for tax invoice to get the authenticity of sellers. VAT must be successful and this largely depends upon the public awareness, honesty, faith and morality of tax officials and the business community. There is a need for willpower and action. It is also found that taxpayers’ awareness programme and tax education play prime role to increase the VAT revenue in Nepal.
La salle de l’Histoire canadienne: recension
Authors: Marshall Dominique
Published: May 2019

Une revue des choix thématiques et muséaux de la salle d’Histoire canadienne dans le contexte des débats historiographiques et politiques entourant l’annonce de la rénovation du Musée et du changement de son nom et de sa vocation : place de l’histoire autochtone, identités nationales, techniques d’engagement avec les citoyens et relations entre générations de visiteurs.
“The Public Is Not Ready for This”: 1969 and the Long Road to Abortion Access
Authors: Ackerman Katrina , Stettner Shannon
Published: May 2019

Using the fiftieth anniversary of the 1969 omnibus bill as an opportunity to reflect on the impact that legislation had on abortion access and experiences in Canada, we examine key legislative and activist moments in the long history of abortion rights in Canada, beginning with the lead up to the 1969 revision. This analysis helps to assess the uneven impact and unintended consequences of the 1969 legislation. We offer an analysis of the existing historiography of abortion in order to both assess trends and identify areas that require further study. We suggest using a reproductive justice framework to examine abortion-related history and politics. By doing so, we hope scholars will uncover what abortion history might look like if we decentre milestone legislation like the omnibus bill.
Broken Rear Wheel Suspension
Authors: Naumann Friedrich Karl , Spies Ferdinand
Published: May 2019

A suspension bushing separated from the disk on the rear wheel suspension of a racing vehicle while under operation on an express highway, causing the wheel to detach from the car. Visual inspection showed fresh turning grooves at four built-up fillet welds on the torus of the outside of the disk. The welding heat and rapid cooling caused the base material of the disk – already with a martensitic structure – to harden throughout the torus, both of which caused cracking in the inner and outer fillets at the transition from bushing to disk. Visual inspection of the other rear wheel showed similar stress cracks in the hardened base material of the transition region as well as the same four welds. Rough finishing and the sharp-edged formation of the cross section transition may have also contributed to the failure. The results of the investigation suggested that machine shops neither execute nor permit repair-welds on highly stressed machine parts and especially vehicle components.
Worn Gears for Fuel Injection Pumps
Authors: Naumann Friedrich Karl , Spies Ferdinand
Published: May 2019

Two fuel injection pump gears that were nitrided in a cyanide bath were submitted by the engine manufacturer for examination of hardness distribution and failure analysis. The gears showed signs of wear after only comparatively brief operation. They were made of normalized unalloyed steel C 45 (Material No. 1.0503) according to DIN 17200 and were normalized. Gear 1 with 1905 h of operation showed at one side pittings on both flanks of the teeth as well as incipient fractures. Gear 2 with 1713 h of operation also showed at one side incipient fractures of the nitride layers at the outer part of the teeth. The nitride layer did not stand up to the high and one-sided compressive stress applied in this case and could not prevent pitting. It could even have accelerated the wear by the incipient break down. Gas nitriding at greater depth under application of a suitable special steel or case hardening would have been better under these circumstances.
Damaged Cylinder Lining from a Diesel Motor
Authors: Kauczor Egon
Published: May 2019

A cast iron cylinder liner from a diesel engine suffered localized damage on the cooling water side leading to serration of the edges and heavy pitting. This heavy damage was cavitation damage, frequently observed in diesel motor cylinders. To combat such damage the following measures are recommended in the specialist literature: reduction in piston play; reduction in the amplitude by thicker-walled linings; hard chromizing of the cooling water side; and, addition of a protective oil to the cooling water. The effect of the protective oil is presumably based on a film of oil which forms on the cylinder surface and which is not so easily scoured off during vibration. The effect of the imploding vacuum bubbles is reduced by the oil film which can renew itself from the emulsion.
An Example of Incidence of Non-Metallic Inclusions in an Alloy Steel
Authors: Chatterjee P. K.
Published: May 2019

There was a large incidence of surface defects on the crank pins and journals and other areas of crank shafts of a high power automotive engine. The steel used was a Cr-Mo type of nitriding steel. Metallographic observations conclusively proved that the defective areas were entrapment of foreign bodies, resulting from steel making/deoxidizing/teeming stages. The occasionally globular nature of the foreign particles suggested these were formed at the liquid condition of the steel. The ratio of Mn-Si as seen on electron probe microanalysis also suggested the globules high in Mn content might have resulted in deoxidizing stage. Particularly the absence of Fe in some areas in the inclusion was indicative of precipitation deoxidation by ferromanganese/ferrosilicon. The defects apparently did not have time to coalesce and rise up to the top.
Discoloration of Open-Circuit Sensor Coil
Authors: Suess S.J.
Published: May 2019

An electronic sensor coil failed continuity testing, indicating that a break was present in the polymer-coated wire. An area of the wire showed a green discoloration and the break in the wire was located in this same region. The discoloration was suspected to be an indicator of what caused the failure. SEM/EDS and FTIR results showed the break in the coil wire was associated with corrosion. The corrosion debris contained relatively high levels of sodium and chlorine, which were likely in the form of salt. Some salt deposits were noted also in other areas along the wire surface. The findings suggested salt or salt water had leaked into the sensor and caused localized corrosion to the wire, possibly at an area where preexisting damage was present in the coating. Separation occurred in the wire when the current density at the reduced cross section caused excessive localized heating, which led to melting of the wire.
Failure of High Tensile Bolts
Authors: Kothari N.C.
Published: May 2019

Six galvanized high-tensile steel bolts were used to hold the wheels of a four-wheel drive vehicle. The right hand rear wheel of this vehicle detached causing the vehicle to roll and resulting in considerable damage to the body. The wheel was detached by shearing of four of the bolts and stripping the nuts from the other two bolts, which remained unbroken. SEM fractography of the fracture surfaces of the four broken bolts indicated that the failure was due to reversed bending fatigue. Optical microscopy indicated that the bolts were heat treated to a tempered martensite structure and that the nuts were manufactured from low carbon steel. The paper discusses the influence of the microstructure on the failure process the events surrounding the nature of incident and the analysis of in-service failure of the failed components utilizing conventional metallurgical techniques.
Metallographic Examination of Microbiologically Influenced Corrosion in a Fire Truck Water Tank
Authors: Ackerson T.N.
Published: May 2019

Several type 304 stainless steel fire truck water tanks developed through-wall leaks after being in service for approximately two years. One representative tank underwent a comprehensive laboratory analysis, which included metallographic examinations and chemical analyses. The examinations revealed a classic case of microbiologically influenced corrosion (MIC), which preferentially attacked the heat affected zones of the tank welds, resulting in the leaks.
Cracking in a Boiler Steam Drum
Authors: da Silveira T.L. , Le May I.
Published: May 2019

During the inspection of a boiler containing cracks at the superheater header connection, cracking also was detected within the main steam drum. This was fabricated from a Mn-Mo-V low-alloy steel. It operated with water and saturated steam at approximately 335 deg C. Cracking was detected at the nozzles connecting the tubes for the entry of steam and hot water to the drum, at the downcomers, and at the connection to the safety valve. All cracks had a similar morphology, running in a longitudinal direction along the drum from the cutouts in the shell. All the cracks had developed under the influence of the hoop stress and were associated with the locally increased stress levels relating to the cutouts at nozzle and pipe connections. At their ends the cracks were filled with corrosion products, and their surfaces were seen to be very irregular. The process of crack growth was not due to fatigue only but can most probably be attributed to corrosion fatigue. The boiler steam drum design should be reviewed to reduce the local level of stress at the shell-nozzle connections.
Failure at a Steam Outlet Collector
Authors: da Silveira T.L. , Le May I.
Published: May 2019

A superheater in a generator produced 80 t/h of steam at 400 deg C and 41 kPa. Failure took place at the connection from the collector to the vent line used during start up. The material of construction was carbon steel, and the unit had 240,000 h of operation at the time of failure, with 99 shutdowns. Widespread cracking on the inside was apparent, the most severe cracking being some distance from the nozzle connection in a downstream direction. Widespread cracking and pitting were observed also at the connections to the safety valve and soot blower. Pitting was most apparent on the downstream sides of the openings in the shell. In all the damaged areas the mechanism of failure involved surface pitting and subsequent SCC. This failure showed the problems that can develop where there are long lines in which condensation may occur and return periodically to a superheater or other hot component. In this particular case, control of dissolved solids in the boiler feedwater may have been inadequate.
Failure of a Superheater Outlet Tube
Authors: da Silveira T.L. , Le May I.
Published: May 2019

After some 87,000 h of operation, failure took place in the bend of a steam pipe connecting a coil of the third superheater of a steam generator to the outlet steam collector. The unit operated at 538 deg C and 135 kPa, producing 400 t/h of steam. The 2.25Cr-1Mo steel pipe in which failure took place was 50.8 mm in diam with a nominal wall thickness of 8 mm. It connected to the AISI 321 superheater tube by means of a butt weld and was one of 46 such parallel connecting tubes. The Cr-Mo tubing was situated outside the heat transfer zone of the superheater. The overall sequence of failure involved overheating of the Cr-Mo outlet tubes, heavy oxidation, oxide cracking on thermal cycling, thermal fatigue cracking plus oxidation, creep-controlled crack growth, and rapid plastic deformation and rupture. This failure was indicative of excess temperature of the steam coming from the heat transfer zone of the coil. It showed that many damage mechanisms may combine in the transition from fracture initiation to final failure. The presence of grain boundary sliding as an indication of creep damage was useful in the characterization of the stress level as high and showed that the process of creep was not operative throughout the life of the equipment.
Examination of Corroded Boiler Tubes
Authors: Naumann Friedrich Karl , Spies Ferdinand
Published: May 2019

A backwell tube situated in the combustion chamber of a 100 atm boiler, which had been in service for many years, failed. The temperature of the saturated steam was about 300 deg C. Two pipe sections with attacked areas in the circumferential welding joint were examined for cause of failure. First section showed strong pit or trench-like attack in the welding seam on the inner surface. A bluish-black corrosion product adhered to the pits. The second section showed small blisters at the welding seam. The metallographic examination of the first section showed welding seam was strongly reduced in bulk from the inside and covered with a thick crumbling layer of magnetic iron oxide (Fe3-O4). This was a corrosion product resulting from the operation of the boiler. In addition, it was decarburized from the inside, and interspersed with grain boundary cracks. This form of attack is typical for the decarburization of steel by high-pressure hydrogen. Hence, the defects in the pipe sections were the result of scaling during the operation of the steam boiler. It was recommended to avoid unnecessary overheating during the welding of materials for high-pressure steam boiler operations.
Fractured Turbine Blades
Authors: Naumann Friedrich Karl , Spies Ferdinand
Published: May 2019

In an electric power station, seven turbine blades out of 112 broke or cracked within 8 to 14 months after commencement of operation. The blades in question were all located on the last running wheel in the low pressure section of a 35,000 kW high pressure condensing turbine. They were milled blades without binding wires and cover band. They did not fracture at the fastening, i.e. the location of highest bending stress, but in a central region which was 165 to 225 mm away from the gripped end. The blades were fabricated from a stainless heat-treatable chromium steel containing 0.2C and 13.9Cr. Microstructural examination showed the blades were destroyed by flexural vibrations which evidently reached their maximum amplitude at the location of fracture. Erosion of the inlet edge, possibly in connection with vibration-induced corrosion cracking, contributed to fracture.
Failure Analysis of Superheater Outlet Header
Authors: Thielsch Helmut , Smoske Robert , Cone Florence , Husband Jason
Published: May 2019

In Nov. 1998, the west superheater outlet header at an electricity generating plant began to leak steam. Subsequent investigation revealed the presence of a crack that extended for 360 deg around the full circumference of the header and through the full cross-sectional thickness. The subsequent inspection of this header and the east superheater header revealed the presence of extremely severe ligament cracking. They operated at 2400 psi (16.5 MPa) and a temperature of 540deg C (1005 deg F). Both were fabricated from seamless pipe produced in accordance with ASME Specification SA-335, and the steel was Grade P22, a 2.25Cr-1Mo alloy steel. Visual and metallurgical evaluations showed the cracking in the west superheater outlet header was caused by thermal fatigue. Tube holes had served as a preferential site for thermal fatigue cracking.
Failure Analysis of Gas Turbine Last Stage Bucket Made of Udimet 500 Superalloy
Authors: Mazur Z. , Kubiak J. , Mariño-Lopez C.
Published: May 2019

This article presents a failure analysis of 37.5 mW gas turbine third stage buckets made of Udimet 500 superalloy. The buckets experienced repetitive integral tip shroud fractures assisted by a low temperature (type II) hot corrosion. A detailed analysis was carried out on elements thought to have influenced the failure process: a) the stress increase from the loss of a load bearing cross-sectional area of the bucket tip shroud by the conversion of metal to the corrosion product (scale), b) influence of the tip shroud microstructure (e.g., a presence of equiaxed and columnar grains, their distribution and orientation), c) evidence of the transgranular initiation, and d) intergranular creep mechanism propagation. The most probable cause of the bucket damage was the combination of increased stresses due to corrosion-induced thinning of the tip shroud and unfavorable microstructures in the tip shroud region.
Pitting Corrosion of Steel Tubes in an Air Preheater
Authors: Vamsi Krishna B. , Sidhu R.K.
Published: May 2019

Severe pitting corrosion of a carbon steel tube was observed in the air preheater of a power plant, which runs on rice straw firing. Approximately 1450 tubes were removed from Stage 3 of the preheater (air inlet and flue gas outlet) due to corrosion and local bursting. Samples from Stage 2 (where corrosion was low) and Stage 3 (severe corrosion) were taken and subjected to visual inspection, SEM, x-ray diffraction, microhardness measurement, and chemical and microstructural analysis. It was determined that extended non-operation of the plant resulted in the settlement of corrosive species on the tubes in Stage 3. The complete failure of the tube occurred due to diffusion of these elements into the base metal and precipitation of potassium and chlorine compounds along the grain boundaries, with subsequent dislodging of grains. The nonmetallic inclusions acted as nucleating sites for local pitting bursting. Nonuniform heat transfer in Stage 3 operation accelerated the selective corrosion of front-end tubes. The relatively high heat transfer in this stage resulted in condensation of some corrosive gases and consequent corrosion. Continuous operation of the plant with some precautions during assembly of the tubes reduced the corrosion problem.
The Identification of the Origins of Some Deposits in a Steam Turbine
Authors: Thornley J. C. , Sutherland J. K.
Published: May 2019

The intermediate pressure (IP) turbine of a thermal generating station is driven by steam from the boiler's reheater. On one particular IP turbine, a thick deposit was found on the insides of the rotor blade shrouds in two instances two years apart. The source of the deposits was not known; bulk chemical analysis had simply shown that iron was a major component. Optical microscopy and electron microprobe analysis were used to identify the deposits. In the first instance, the deposit was found to be debris that was left in the reheater tubes during boiler modification and swept to the turbine by the steam. There were still some of these debris particles present when the incident two years later was investigated but generally the second deposit was found to be of two layer oxide particles which were shown to have spalled from 2-14% chromium reheater tube surfaces.
Field Metallography Aids NDT of Evaluation of Indications in Turbine Main Column Horizontal Plate Welds at Power Plant
Authors: Diaz David J. , Benson Steve E.
Published: May 2019

An evaluation of indications in the main turbine building column horizontal plate welds was conducted by the joint efforts of field metallography and nondestructive examinations. The turbine building main column horizontal plate welds were selected at random and were inspected to find discontinuities, metallurgical evaluation of the discontinuities, analysis of any failure modes, and determination of the best repair techniques. The welds were made with prequalified joints in accordance with AWS D1.1-77 and required only visual inspection. More sensitive inspection methods were applied to the welds in order to better define the indications found with the visual inspections. Cracks were found in 17 field welds and in two test plate welds. The causes of the cracking are related to the weld design and installation procedure. Three field welds were rejected because of the depth of the cracks. The NDT inspections, evaluations, method of field metallography, analysis and conclusions are discussed with recommendations for corrective actions in the following report.
Failure Investigation of Longitudinal Seam Welded Elevated Temperature Header
Authors: Henry J. F. , Ellis F. V. , Alice J. , LaFontaine J. K. , Orban P. C.
Published: May 2019

As the result of a leak detected in a plate-formed header at PENELEC'S Shawville Unit No. 3, an extensive failure investigation was initiated to determine the origin of cracking visible along the longitudinal weld seam. Fabricated from SA387-D material and designed for a superheater outlet temperature of 566 deg C, the 11.4 cm thick header had operated for approximately 187,000 h at the time of the failure. Discussion focuses on the results of a metallographic examination of boat samples removed from the longitudinal seam weldment in the vicinity of the failure and at other areas of the header where peak temperatures were believed to have been reached. The long-term mechanical properties of the service-exposed base metal and creep-damaged weld metal were determined by creep testing. Based on the utility's decision to replace the header within one to three years, an isostress overtemperature lead specimen approach was taken, whereby failure of a test specimen in the laboratory would precede failures in the plant. These tests revealed approximately a 2:1 difference in life for the base metal as compared to weld metal.
Failure of Inconel 600 Thin-Walled Tubes Due to Nitriding
Authors: Griffiths M. , Slade J. P. , McDonald A. M.
Published: May 2019

The self-powered flux detectors used in some nuclear reactors are Pt or V-cored co-axial cables with MgO as an insulator and Inconel 600 as the outer sheath material. The detectors are designed to operate in a He atmosphere; to maximize the conduction of heat (generated from the interaction with gamma radiation) and to prevent corrosion. A number of failures have occurred over the years because of a loss of the He cover gas in the assembly. This has resulted in either acid attack on the Inconel 600 sheath in a wet environment or gaseous corrosion in a dry environment. In the latter case, nitriding and embrittlement occurred at temperatures as low as 300 to 400 deg C (determined from an examination of the oxidation of the Zircaloy-2 carrier rod on which the detectors were mounted). Recent results are described and discussed in terms of the oxidation and nitriding kinetics of Zircaloy-2 and Inconel 600, respectively.
Analysis of Mercury Diffusion Pumps
Authors: Dunn Kerry A.
Published: May 2019

Several mercury diffusion pump stages in the Tritium Purification process at the Savannah River Site (SRS) have been removed from service for scheduled preventive maintenance. These stages have been examined to determine if failure has occurred. Evidence of fatigue around the flange portion of the pump has been seen. In addition, erosion and cavitation inside the throat of the venturi tube and corrosion on the other surface of the venturi tube has been observed. Several measures are being examined in an attempt to improve the performance of these pumps. These measures, as well as the noted observations, are described. Six stages [two machined (MP) and four electron beam (EB) welded] from the mercury diffusion pumps operating in the Tritium Purification process at SRS have been analyzed to determine their condition after nine months of usage. Several cracks were found around the necked region of the two MP stages. The EB welded stages, however, seemed to perform better in service; only two of four stages showed cracking. The cracking is caused by fatigue that has been enhanced by high stresses and tritium in the flange area. The EB welded stage appears to be a step in the right direction. Since the EB weld is a shrink fit, the surface is in compression, thereby eliminating crack propagation. In addition, shot peening has been employed to produce a compressive material surface since fatigue usually originates at the surface. Pitting was observed down the throat of the venturi. This pitting was caused by cavitation and erosion along the length of the venturi tube. Corrosion and pitting was seen on the exterior walls of the diffuser tubes. Stress-corrosion cracks were observed emanating from these corrosion pits. The corrosion likely occurred from the chloride ions present in the process cooling water. Shot peening is now being used in an attempt to place the outside of the diffuser tube in compression to eliminate the stress-corrosion cracking.
Wind Turbine Failures
Authors: May I. Le , Bagnall C.
Published: May 2019

Two blade-detachment failures in large (600 kW) wind turbine generators were investigated. In the first case, bolt failures were established as the initial failure event. A fatigue crack reached a critical length, fast fracture developed and was then arrested as the bolt unloaded. Crack growth resumed when loading increased with cracking or fracture of adjacent bolts. The problem was identified as one of insufficient preload on the bolts. In the second failure on a different unit, a retaining nut on a blade assembly split, allowing a roller bearing to slide off a shaft and a blade to separate at its attachment hub. The failure was observed to be by fatigue. It was determined that pieces of the outer retaining rib (or flange) on the bearing inner cage had fractured by fatigue and were trapped between the nut and the bearing, producing excessive cyclic loading on the nut by a wedging action as the blade pitch adjusted during a revolution. Fatigue of the rim occurred as a result of inadequate lubrication in the bearing, which led to load transfer across the rollers, onto the rim.
Creep Failure Analysis of Steel Tubes
Authors: Pero-Sanz J.A. , Plaza D. , Ruiz M. , Asensio J. , Verdeja J.I.
Published: May 2019

Failures of 10Cr-Mo9-10 and X 20Cr-Mo-V12-1 superheated pipes during service in steam power generation plants are described. Through micrographic and fractographic analysis, creep and overheating were identified as the cause of failure. The Larson-Miller parameter is computed, as a function of oxidation thickness, temperature and time, confirming the creep failure diagnostic.
Another Turbogenerator Failure
Authors: James Landrum R.
Published: May 2019

Another failure in a turbogenerator, similar to the accidents in Toronto described in Metal Progress in July 1956, was due to the presence of fatigue cracks at ventilating holes. These acted as stress-raisers during temporary and minor overspeeding, inducing an almost instantaneous brittle failure which wrecked the machine, fortunately without human casualty.
Failure of Recuperator with Austenitically Welded Pipes
Authors: Naumann Friedrich Karl , Spies Ferdinand
Published: May 2019

A recuperator used for preheating the combustion air for a rolling mill furnace failed after a relatively short service time because of leakage of the pipes in the colder part. The 6 % chrome steel pipes used for the warmer part connected by means of welding with austenitic electrodes to the unalloyed mild steel pipe of larger diam. Visual inspection showed corrosion and deep, trench-like erosion over the entire circumference of the seam on the side of the thicker mild steel pipe. Examination using the V2-A solution for picral etch showed the microstructure of the unalloyed pipe had become coarse-grained and acicular, and the microstructure of the welding seam had become predominantly martensitic as a result of the mixing of the weld metal with the fused pipe material. The chrome steel pipe had become partially transformed to martensite or bainite at the transition to the weld. Thus, the failure occurred due to typical contact corrosion wherein the alloyed welding seam represented the less noble electrode. The martensitic structure may have contributed to the failure as well. Due to the typical nature of the failure, no recommendations were made.
Fractured Swivel Head
Authors: Naumann Friedrich Karl , Spies Ferdinand
Published: May 2019

The swivel head of a driving spindle of a four-high mill fractured. The fracture originated in a darkly stained spot on the bottom of the cylindrical part and then continued into the cylinder walls in the two directions. The fracture topography was of dendritic structure at the stained spot. This led to the conclusion that a shrinkage cavity was present. Metallographic examination confirmed that the fracture of the swivel head was caused or favored by a cavity.
Fractured Recuperator Made of Heat Resistant Cast Steel
Authors: Naumann Friedrich Karl , Spies Ferdinand
Published: May 2019

A recuperator for blast heating of a cupola furnace became unserviceable because of the brittle fracture of several finned tubes made of heat resistant cast steel containing 1.4C, 2.3Si and 28Cr. The service temperature was reported as 850 deg C. This led to the suspicion that the fracturing had something to do with the precipitation of sigma phase. Metallographic examination showed that the multiaxial stresses caused by sigma phase formation and the related embrittlement was the cause for the fracture of the recuperator. A steel of lower chromium content with no or little tendency for sigma phase formation would have had adequate corrosion resistance at the relatively low service temperature.
Examination of an Oxidized Heating Coil
Authors: Naumann Friedrich Karl , Spies Ferdinand
Published: May 2019

A coil made of a nickel-chromium alloy (Material No. 2.4869) with approx. 80Ni and 20Cr had burned through after a brief period of operation as a heating element in a brazing furnace. The protective atmosphere consisted of an incompletely combusted coal gas. Furnace temperature reached 1150 deg C. This type of selective oxidation at which the easily oxidized chromium burns, while the nickel is not attacked, is caused by mildly oxidizing gases and is sometimes designated as green rot. Under these conditions, chromium-containing steels and alloys whose oxidation resistance is based upon formation of tight oxide layers are not stable.
Metallurgical Investigation of a Prematurely Failed Roller Bearing Used in the Support and Tilting System of a Steel Making Converter Used in an Integrated Steel Plant
Authors: Ray Amitava , Dhua S.K. , Mishra K.B. , Jha S.
Published: May 2019

An extensive metallurgical investigation was carried out on samples of a failed roller bearing from the support and tilting system of a basic oxygen furnace converter used in the steel melting shop of an integrated steel plant. The converter bearing was fabricated from low-carbon, carburizing grade steel and had failed in service within a year of fitting to a repaired shaft. Microscopic observations of both the broken roller and inner-race samples revealed subsurface cracking and preponderance of brittle oxide and other macroinclusions. Electron probe microanalysis studies confirmed that the brittle oxides that formed stringers were alumina, and the other macroinclusions were complex silicates. Both the alumina and silicate inclusions were deleterious to contact-fatigue properties. Microstructurally, the carburized regions of the broken roller and of inner-race samples contained high-carbon tempered martensite. Microhardness measurements revealed that. Although the core hardness of the roller and the inner-race samples were similar, the surface hardness of the roller was approximately 8.5 HRC units harder than that of the inner-race. SEM observations of the roller fracture surface revealed striations indicative of fatigue, and EDS analyses corroborated a high incidence of silicate inclusions at crack sites. The study suggests that the failure of the bearing occurred because the hardness difference between the roller bearing and the inner-race surfaces resulted in wear of the inner-race. The wear led to shaft misalignment and play during service. The misalignment, coupled with the presence of inclusions, caused fatigue failure of the roller bearing.
Integrated Analysis of an Autoclave Failure
Authors: Shaw W. J. D.
Published: May 2019

A detailed investigative failure analysis was conducted on an autoclave which blew apart in a furnace for no apparent reason. Bolt failure resulted in separation of the autoclave lid and subsequent destruction of the furnace. Analysis using metallography, fractography, mechanical testing and exemplar tests were performed on the bolt material. Mechanical engineering analysis and leak-before-break criteria were extensively analyzed. Results led to only one possible conclusion: that an explosion occurred within the autoclave. Suggestions for autoclave design are presented as a result of the analysis.
Case of Metal Dusting on HK40 HyL III Radiant Pipe Heat Exchanger
Authors: Koswara
Published: May 2019

In a HyL III heat exchanger's radiant pipes, metal dusting reduced the pipe thickness from 8.5 to 3 mm in just nine months, leaving craters on the inner surface. The pipes are fabricated from HK 40 alloy. The heated gas (400 to 800 deg C) consisted of CO, CO2, and H2, with a 4:1 CO/CO2 ratio. Metallographic investigations revealed that the surface of the attacked pipes consisted of (Cr, Fe) carbide. The metal dusting was the result of a decomposition process (CO to CO2 + C) that deposited C on the pipe surface. Because of the high temperature, the C subsequently diffused through the surface oxide layer (Cr2O3), triggering a succession of reactions that led to pitting and the formation of craters.
Fascicular torsions of the anterior and posterior interosseous nerve in 4 cases: neuroimaging methods to improve diagnosis
Authors: Kollmer Jennifer , Preisser Paul , Bendszus Martin , Kele Henrich
Published: May 2019

Diagnosis of spontaneous fascicular nerve torsions is difficult and often delayed until surgical exploration is performed. This case series raises awareness of peripheral nerve torsions and will facilitate an earlier diagnosis by using nerve ultrasound (NUS) and magnetic resonance neurography (MRN). Four patients with previously ambiguous upper-extremity mononeuropathies underwent NUS and 3T MRN. Neuroimaging detected proximal torsions of the anterior and posterior interosseous nerve fascicles within median or radial nerve trunks in all patients. In NUS, most cases presented with a thickening of affected nerve fascicles, followed by an abrupt caliber decrease, leading to the pathognomonic sausage-like configuration. MRN showed T2-weighted hyperintense signal alterations of fascicles at and distal to the torsion site, and directly visualized the distorted nerves. Three patients had favorable outcomes after being transferred to emergency surgical intervention, while 1 patient with existing chronic muscle atrophy was no longer eligible for surgery. NUS and MRN are complementary diagnostic methods, and both can detect nerve torsions on a fascicular level. Neuroimaging is indispensable for diagnosing fascicular nerve torsions, and should be applied in all unclear cases of mononeuropathy to determine the diagnosis and if necessary, to guide surgical therapies, as only timely interventions enable favorable outcomes.
Predictors of favorable quality of life outcome following kyphoplasty and vertebroplasty
Authors: Jones Jaes C. , Miller Jacob A. , Sudarshana Dattanand M. , Thompson Nicolas R. , Benzel Edward C. , Mroz Thomas E.
Published: May 2019

OBJECTIVE

In 2009, 2 randomized controlled trials demonstrated no improvement in pain following vertebral augmentation compared with sham surgery. However, a recent randomized trial demonstrated significant pain relief in patients following vertebroplasty compared to controls treated with conservative medical management. This study is a retrospective review of prospectively collected patient-reported quality of life (QOL) outcomes. The authors hypothesized that vertebral augmentation procedures offer a QOL benefit, but that this benefit would be diminished in patients with a history of depression and/or in patients undergoing vertebral augmentation at more than 1 level.

METHODS

Multivariable linear regression was used to identify predictors of postoperative pain assessed using the Pain Disability Questionnaire (PDQ), Patient Health Questionnaire 9 (PHQ-9), and EQ-5D scores. Eleven candidate predictors were selected a priori: age, sex, smoking history, coronary artery disease, depression, diabetes, procedure location (thoracic, lumbar), BMI, prior spine surgery, procedure indication (metastases, osteoporosis/osteopenia, other), and number of levels (1, 2, 3, or more).

RESULTS

A total of 143 patients were included in the study. For each 10-year increase in age, postoperative PDQ scores decreased (improved) by 9.7 points (p < 0.001). Patients with osteoporosis/osteopenia had significantly higher (worse) postoperative PDQ scores (+17.97, p = 0.028) than patients with metastatic lesions. Male sex was associated with higher (worse) postoperative PHQ-9 scores (+2.48, p = 0.010). Compared to single-level augmentation, operations at 2 levels were associated with significantly higher PHQ-9 scores (+2.58, p = 0.017). Current smokers had significantly lower PHQ-9 scores (−1.98, p = 0.023) than never smokers. No predictors were associated with significantly different EQ-5D score.

CONCLUSIONS

Variables associated with worse postoperative PDQ scores included younger age and osteoporosis/osteopenia. Variables associated with decreased (better) postoperative PHQ-9 scores included female sex, single operative vertebral level, and positive smoking status (i.e., current smoker). These clinically relevant predictors may permit identification of patients who may benefit from vertebral augmentation.
EFEKTIVITAS MODEL PEMBELAJARAN INKUIRI TERBIMBING MELALUI METODE DEMONSTRASI TERHADAP HASIL BELAJAR PSIKOMOTORIK SISWA
Authors: Patimapat Marselina , Duda Hilarius Jago , Supiandi Markus Iyus
Published: May 2019

Tujuan penelitian ini adalah untuk mengetahui Efektivitas Model Pembelajaran Inkuiri Terbimbing melalui Metode Demostrasi terhadap Hasil Belajar Psikomotorik Siswa. Metode yang digunakan dalam penelitian ini adalah metode kuantitatif. Bentuk penelitian yang digunakan yaitu quasi-eksperimen dengan desain penelitian nonequivalent control group design. Sampel dalam penelitian ini berjumlah 21 siswa pada kelas eksperimen dan 20 siswa pada kelas kontrol. Teknik pengumpulan data menggunakan teknik observasi langsung, teknik pengukuran, dan teknik komunikasi tidak langsung. Alat pengumpulan data yang digunakan adalah lembar observasi, tes untuk kerja, dan angket. Hasil analisis lembar observasi guru pertemuan pertama dan kedua diperoleh nilai rata-rata persentase sebesar 100%, yang berkriteria sangat baik, sedangkan analisis lembar observasi siswa pada pertemuan pertama dan kedua diperoleh nilai rata-rata persentase sebesar 95,40% yang berkriteria sangat baik. Hasil analisis nilai Effect Size (ES) diperoleh nilai sebesar 0,7 dengan kriteria sedang. Hal ini menunjukkan bahwa penggunaan model pembelajaran inkuiri terbimbing melalui metode demostrasi cukup efektif digunakan untuk meningkatkan hasil belajar psikomotorik siswa. Berdasarkan pengolahan data angket respon siswa diperoleh rata-rata nilai persentase sebesar 86,03% dengan kategori sangat kuat.