bluuebunny/crossref_metadata_2025_split huggingface dataset:
Galvanic Corrosion Failure of Austenitic Stainless Steel Pipe Flange Assemblies
Authors: Lochanski Edward C. 
Published: May 2019

Abstract
Catastrophic pitting corrosion occurred in type 304L stainless steel pipe flange assemblies in an industrial food processor. During regular service the pumped medium was pureed vegetables. In situ maintenance procedures included cleaning of the assemblies with a sodium hypochlorite solution. It was determined that the assemblies failed due to an austenite-martensite galvanic couple activated by a chlorine bearing electrolyte. The martensitic areas resulted from a transformation during cold-forming operations. Solution annealing after forming, revision of the design of the pipe flange assemblies to eliminate the forming operation, and removal of the source of chlorine were recommended.
Leaks in Copper Tubing From Cooling Coils of a Large Air-Conditioning Unit
Authors: Edwards J.O. , Hamilton R.I. 
Published: May 2019

Abstract
Copper tubes from the cooler assemblies of a large air-conditioning unit exhibited leakage upon installation of the unit. Sections from two leaking tubes and one nonleaking tube were subjected to pressure testing and microscopic examination. The cause of leaking was determined to be pitting corrosion. Extensive pitting was found on the insides of all sections examined, with deep and numerous pits in leaking areas. Circumstantial evidence indicated that antifreeze solution left in the tubes from the manufacturing operation was the most likely cause of the pitting.
Short-Term Failure of Carbon Steel Boiler Tubes
Authors: Bigelow Clifford C. 
Published: May 2019

Abstract
Two identical “D” tube package boilers, installed at separate plants, experienced a number of tube ruptures after relatively short operating times. The tubes, which are joined by membranes, experienced localized bulging and circumferential cracking along the fireside crown as a result of overheating and thermal fatigue. It was recommended that recent alterations to the steam-drum baffling be remodified to improve circulation in the boiler and prevent further overheating. Several thermocouples were attached to tubes in problem areas of the boiler to monitor the effects of the steam-drum modifications on tube wall temperatures.
Stress-Corrosion Cracking in a Stainless Steel Emergency Injection Pipe in a Nuclear Reactor
Authors: Muraleedharan P. , Gnanamoorthy J.B. 
Published: May 2019

Abstract
A section of type 304 stainless steel pipe from a stand by system used for emergency injection of cooling water to a nuclear reactor failed during precommissioning. Leaking occurred in only one spot. Liquid penetrant testing revealed a narrow circumferential crack. Metallographic examination of the cracked area indicated stress-corrosion cracking, which had originated at rusted areas that had formed on longitudinal scratch marks on the outer surface of the pipe. The material was free from sensitization, and there was no significant amount of cold work. It was recommended that the stainless steel be kept rust free.
Failure of a Reversible Flap Valve in a Thermal Power Station
Authors: Vasu K.K. 
Published: May 2019

Abstract
A reversible four-way carbon steel flap valve in a thermal power station failed after 7 years of service. The flap had been fabricated by welding two carbon steel plates to both sides of a carbon steel forging. The valve was used for reversing the flow direction of seawater in the cooling system of a condenser. Visual examination of the flap showed crystalline fracture, indicating a brittle failure. Metallographic examination, chemical analyses, and tensile and impact testing indicated that the failure was caused by the notch sensitivity of the forging material, which resulted in low toughness. It was recommended that fully killed carbon steel with a fine-grain microstructure be used. Redesign of the flap to remove the step in the forging that acted as a notch was also recommended.
Aluminum/Refrigerant Reaction Resulting in the Failure of a Centrifugal Compressor
Authors: Studer Anthony C. 
Published: May 2019

Abstract
An investigation of the impeller and deposit samples from a centrifugal compressor revealed that an aluminum IR-12 refrigerant reaction had occurred, causing extensive damage to the second-stage impeller and contaminating the internal compressor components. The spherical surface morphology of the impeller fragments suggested that the aluminum had melted and resolidified. The deposits were similar in composition and were identified by XRD as consisting primarily of aluminum trifluoride. In addition, EDS analysis detected major amounts of chlorine and iron. Results of a combustion test indicated that the compressor deposit was comprised of a 9. 8 wt% carbon and that the condenser deposit contained 8.7 wt% carbon. It was concluded that the primary cause of failure was the rubbing of the impeller against the casting and that a self-sustaining Freon fire had occurred in the failed compressor
Failure Analysis of a Hydroturbine Shaft
Authors: McCann Donald R. , Harry Michael V. 
Published: May 2019

Abstract
A forged 4140 steel shaft that connected two runners in a hydroturbine failed catastrophically after approximately 5900 h of service. The runner and the mating section of the broken shaft were examined and tested by various methods. The results of the analyses indicated that the shaft failed by torsional fatigue starting at subsurface crack initiation sites. The forging contained regions of crack like flaws associated with particles rich in chromium, manganese, and iron. Fracture features indicated that the fatigue cracks propagated under a relatively low stress.
Dezincification of a Chrome-Plated Cylinder Gas Valve
Authors: Colwell Richard L. 
Published: May 2019

Abstract
Two new chrome-plated CDA 377 brass valves intended for inert gas service failed on initial installation. After a pickling operation to clean the metal, the outer surfaces of the valves had been flashed with copper and then plated with nickel and chromium for aesthetic purposes. One of the valves failed by dezincification. The porous copper matrix could not sustain the clamping loads imposed by tightening the pressure relief fitting. The second valve failed by shear overload of the pressure relief fitting. Overload was facilitated by a reduction of cross-sectional area caused by intergranular attack and slight dezincification of the inner bore surface of the fitting. Dezincification and intergranular attack were attributed to excessive exposure to nonoxidizing acids in the pickling bath.
Failure of Three Valve Body Castings
Authors: Goodrich George M. 
Published: May 2019

Abstract
Three sprinkler system dry pipe valve castings (class 30 gray iron), two that had failed in service and one that had been rejected during machining because of porosity, were submitted for examination. The two failures consisted of cracks in a seating face. All three were from the same heat. Visual examination showed that the casting had cracked through a thin area in the casting sidewall. Evidence of a sharply machined corner at the fracture site was also discovered. Tensile testing and metallographic analysis revealed no metallurgical cause for the failure. It was recommended that the manufacturer work with the foundry to evaluate the criticality of core placement and to eliminate the undesired thin section.
Fracture of a Spike Maul
Authors: D'Antonio Carmine 
Published: May 2019

Abstract
An AISI 9260 steel railroad spike maul failed after a relatively short period of service. The maul head fractured in two pieces when struck against a rail. Visual, fractographic, metallographic, and chemical analyses were conducted on sections taken from the maul head, which was found to have fractured across both sides of the eye. Failure occurred in at least three separate events: formation of two cracks immediately adjacent to the eye, extension of one of the original cracks over a portion of one of the eye sides, and abrupt extension of the original crack across the eye sides, resulting in separation into two halves.
Hydrogen-Assisted Stress Cracking of Carburized and Zinc Plated SAE Grade 8 Wheel Studs
Authors: Baggerly Roy G. 
Published: May 2019

Abstract
Several case-hardened and zinc-plated carbon-manganese steel wheel studs fractured in a brittle manner after very limited service life. The fracture surfaces of both front and rear studs showed no sign of fatigue beach marks or deformation in the form of shear lips that would indicate either a fatigue mechanism or ductile overload failure. SEM analysis revealed that the mode of fracture was intergranular decohesion, which indicates an environmental influence in the fracture mechanism. The primary fracture initiated at a thread root and propagated by environmentally-assisted slow crack growth until final fracture. The natural stress concentration at the thread root, when tightened to the required clamp load concomitant with the presence of cracks in the carburized case, was sufficient to exceed the critical stress intensity for hydrogen-assisted stress cracking (HASC). The zinc plating exacerbated the situation by providing a strong local corrosion cell in the form of a sacrificial anode region adjacent to the cracked thread. The enhanced generation of hydrogen in a corrosive environment subsequently lead to HASC of the wheel studs.
Corrosion Fatigue Failure of Stainless Steel Load Cells in a Milk Storage Tank
Authors: Collins Daryl C. 
Published: May 2019

Abstract
Two type 420 martensitic stainless steel load cell bodies, which had been installed under two of the four legs of a milk storage tank failed in service. The failure occurred near a change in section and involved fracture of the entire cross section. Examination showed a brittle fracture that was preceded by a small fatigue region. Pitting corrosion was evident at the fracture origin. The areas around the load cells had been subjected to regular washdowns using high-pressure hot water, and the pitting was attributed to crevice corrosion between the load cell and the holddown bolts. Prevention of such corrosion by the use of a flexible sealant to eliminate the crevice was recommended.
Formation of Refractory Films on Metal Contacts in an Electrical Switchgear
Authors: Hopkins John R. 
Published: May 2019

Abstract
During routine quality control testing, small circuit breakers exhibited high contact resistance and, in some cases, insulation of the contacts by a surface film. The contacts were made of silver-refractory (tungsten or molybdenum) alloys. Infrared analysis revealed the film to be a corrosion layer that resulted from exposure to ammonia in a humid atmosphere. Simulation tests confirmed that ammonia was the corrodent. The ammonia originated from the phenolic molding area of the plant. It was recommended that fumes from molding areas be vented outside the plant and that assembly, storage, and calibration areas be isolated from molding areas.
Stress-Corrosion Cracking in Stainless Steel Heater Sheathing
Authors: Muraleedharan P. , Khatak H.S. , Gnanamoorthy J.B. 
Published: May 2019

Abstract
Cracking occurred in type 304L stainless steel sheaths on nichrome wire heaters that had been in storage for about 5 years in a coastal atmosphere. The cracks were discovered when the heater coils were removed from storage in their original polyethylene packing materials and straightened for use. Fractography established that fracture occurred by stress-corrosion cracking. The cracks originated at rusted areas on the cladding that occurred under iron particles left on the surface during manufacture. High hardness values indicated that solution annealing following cold working had not been carried out as specified. It was recommended that the sheathing material be fully annealed and that the outer surface be pickled and passivated.
EVALUASI KESIAPAN GURU FISIKA SMA DALAM KEGIATAN LABORATORIUM DI KOTA MATARAM
Authors: Isnaini M , Anwar Kharil 
Published: May 2019

Tujuan penelitian ini adalah untuk mengetahui kesiapan guru fisika SMA dalam kegiatan laboratorium. Kesiapan guru fisika SMA dalam kegiatan laboratorium dapat diketahui dari: (1) kompetensi laboratorium guru fisika SMA dalam merancang kegiatan laboratorium; (2) sarana prasarana laboratorium; (3) hambatan-hambatan yang ditemui guru fisika SMA dalam melaksanakan kegiatan laboratorium; dan (4) langkah-langkah guru fisika SMA mengatasi hambatan dalam melaksanakan kegiatan laboratorium, sehingga hasil temuan ini dapat digunakan sebagai masukan bagi: (1) guru fisika SMA untuk meningkatkan kompetensinya dalam kegiatan laboratorium; (2) Kemendikbud, Dinas Dikpora Kota Mataram dan Provinsi NTB untuk meningkatkan kompetensi kegiatan laboratorium guru fisika SMA melalui pelatihan-pelatihan tentang laboratorium; (3) Lembaga Pendidik Tenaga Keguruan (LPTK) diharapkan meningkatkan kualitas lulusan calon guru fisika dalam kegiatan laboratorium. Penelitian ini menggunakan pendekatan deskriptif kualitatif dengan metode pengumulan data berupa dokumentasi, angket, wawancara dan observasi. Populasi penelitian ini adalah guru fisika SMA se-Kota Mataram yang terdiri dari 8 SMA Negeri dan 10 SMA Swasta berjumlah 32 orang. Sampel penelitian adalah 20 orang guru fisika SMA se-Kota Mataram yang terdiri dari 14 guru SMAN, 6 guru SMA Swasta. Ke-20 guru sampel tersebar di 7 SMA Negeri dan 6 SMA Swasta. Berdasarkan informasi dan analisis yang dilakukan kesiapan guru fisika kota mataram dalam kegiatan laboratorium dikategorikan cukup siap, yang dapat dilihat dari: (a) kompetensi guru fisika SMA dalam kegiatanlaboratorium cukup baik, yaitu sebesar 52%, (b) Kondisi sarana prasarana laboratorium fisika kategori cukupbaik, yaitu sebesar 63.1%, (c) Faktor penghambat kegiatan laboratorium berupa gedung/ruangan sebesar56% dalam ketegori cukup banyak, pengelolaan laboratorium sebesar 70% berkategori cukup banyak, dan alat dan bahan kegiatan laboratorium, sebesar 56% berkategori cukup banyak, dan (d) Langkah-langkah dalam mengatasi hambatan kegiatan laboratorium gedung/ruang laboratorium dikategorikan cukup baik,yaitu sebesar 70%, pengelolaan laboratorium berkategori cukup baik, sebesar 57% dan alat dan bahan kegiatanlaboratorium sebesar 58%, dalam ketegori cukup baik. Saran yang dapat diberikan dari hasil penelitian ini adalah diharapkan agar instansi terkait lebih sering memberikan pelatihan terhadap kegiatan laboarotium untuk meningkatkan kompetensi guru dalam kegiatan laboratorium khususnya kegiatan prosedur percobaan inquiri atau keterampilan proses dan alat evaluasi kegiatan laboratorium.
MENINGKATKAN KUALITAS PEMBELAJARAN SEJARAH ASIA TIMUR MELALUI PENERAPAN METODE INKUIRI DI JURUSAN PENDIDIKAN SEJARAH FKIP UM MATARAM
Authors: Afandi Ahmad 
Published: May 2019

Penelitian ini bertujuan untuk meningkatkan kualitas pembelajaran mata kuliah Sejarah Asia Timur di Program Studi Pendidikan Sejarah Fakuktas Keguruan dan Ilmu Pendidikan Universitas Muhammadiyah Mataram, melalui penerapan dan pengembangan model inkuiri. Pengembangan model ini dilatarbelakangi oleh perlunya dinamisasi dalam proses pembelajaran, sehingga dapat menghasilkan pembelajaran bermakna. Meningkatkan kualitas pembelajaran mahasiswa dalam pengertian mencari, menemukan, dan memecahkan permasalahan dalam perkuliahan dengan penerapan metode inkuiri, yang pada dasarnya juga merupakan penerapan metode sejarah kritis yakni: heuristik, kritik, interpretasi, dan historiografi. Metode yang digunakan dalam penelitian ini adalah penelitian kualitatif dengan strategi kaji tindak berbasis kelas atau penelitian tindakan kelas. Pemilihan metodeini berdasarkan asumsi bahwa perbaikan proses kegiatan pembelajarandi dalam kelas dapat dilaksanakan pengajar dengan melakukan refleksi tentang berbagai hal yang telah dilakukan dalam proses kegiatan pembelajaran, seperti penentuan tujuan pembelajaran, penyusunan materi ajar, sumber buku acuan yang digunakan, strategi pembelajarannya, alokasi waktu yang digunakan dan evaluasi. Aktivitas pengimplementasian tujuan penelitian ini dilakukan dengan pendekatan partisipatif kolaboratif antara pimpinan program, dosen, dan peneliti, sehingga terjadi sharing dalam penyusunan perencanaan tindakan. Hasil penelitian ini menunjukkan bahwa terjadi peningkatan kualitas pembelajaran pada mahasiswa semester III Program Studi Pendidikan Sejarah Fakuktas Keguruan dan Ilmu Pendidikan Universitas Muhammadiyah Mataram melaluipengembangan dan penerapan model inkuiri. Strategi inkuiri yang diterapkan diawali dengan strategi ekspositori yang menempatkan peranan besar dosen dalam pembelajaran terutama dalam hal membina, mengarahkan, membimbing, memberi tindakan, dan mengevaluasi serta refleksi, dan diakhiri dengan strategi inkuiri yangmenuntut kemandirian mahasiswa dalam proses mencari, menemukan, dan memecahkan permasalahan yang berkaitan dengan masalah-masalah yang diajukan oleh dosen. Oleh karena itu, penelitian inikuiri ini tepat jikadesebut sebagai model inkuiri terpimpin.
PENINGKATAN KINERJA GURU DALAM MELAKSANAKAN PENILAIAN BERBASIS KELAS MELALUI SUPERVISI AKADEMIK KEPALA SEKOLAH DI SDN BEBIE
Authors: Muhadis Muhadis 
Published: May 2019

Abstrak: Tujuan diadakan Penelitian untuk mengetahui sejauh mana peningkatan kinerja guru dalam melaksanakan penilaian berbasis kelas melalui supervisi akademik Pengawas di SDN Bebie Kec.Praya Kab. Lombok Tengah tahun pelajaran 2016/2017. Hasil nilai 68,88 pada siklus l dengan prosentase kinerja guru secara kelompok/klasikal 37,5%, dapat meningkat pada siklus 2 menjadi 80,63 dengan prosentase kinerja guru secara kelompok/klasikal 100% sudah melebihi dari standar 85%. disimpulkan bahwa penerapan supervisi akademik Kepala Sekolah dapat meningkatkan kinerja guru dengan ketuntasan kelompok/kalsikal mencapai 100 %, dengan demikian penerapan supervisi akademik Kepala Sekolah efektif meningkatkan kinerja guru dalam melaksanakan penilaian berbasis kelas di SDN Bebie Lombok Tengah.Abstract: The purpose of this study to determine the extent to which improvements in teacher performance in implementing classroom-based assessment through supervision supervision supervision at SDN Bebie District Praya Central Lombok Tengah academic year 2016/2017. The result of score 68,88 in cycle 1 with the percentage of teacher performance in group / classical 37,5%, can increase in cycle 2 to 80,63 with the percentage of teacher performance in group / classical 100% already exceed from standard 85%. it is concluded that the application of academic supervision of principal can improve teacher performance with group / classical completeness reach 100%, thereby applying of principal academic supervision effectively improve teacher performance in carrying out class-based assessment at SDN Bebie Lombok Tengah.
IMPLEMENTASI METODE MIND MAPPING UNTUK MENINGKATKAN MINAT DAN KOMPETENSI WRITING SISWA KELAS VII D SMPN 5 KOPANG
Authors: Abdul Gani Ruslan 
Published: May 2019

Abstrak: Penelitian Tindakan Kelas dilakukan 2 siklus terhadap kelas VII D SMPN 5 Kopang tahun 2014/2015, menggunakan metode pengumpulan data Observasi, Interview, dan dokumentasi, serta tes tentang peningkatan kompetensi dan prestasi writing siswa.. diperoleh nilai rata-rata prestasi dan kompetensi writing bahwa ketuntasan klasikal pada siklus I 89%. Sedangkan pada siklus II terjadi peningkatan ketuntasan klasikal sebesar 6% menjadi 95 %. Disimpulkan bahwa penerapan metode mind mapping dapat meningkatkan minat dan kompetensi writing siswa pada pembelajaran procedure text kelas VII-D SMP Negeri 5 Kopang tahun pelajaran 2014/2015. Abstract: Classroom Action Research conducted 2 cycles to class VII D SMPN 5 Kopang year 2014/2015, using Observation data collection method, Interview, and documentation, and test about improving competence and writing achievement of student .. obtained by average value of achievement and competence writing that classical completeness in cycle I 89%. While in cycle II there is increase of classical mastery by 6% to 95%. It was concluded that the application of mind mapping method can increase interest and writing competence of students on learning text procedure of class VII-D of SMP Negeri 5 Kopang for academic year 2014/2015.
A PHARMACOLOGICAL STUDY ON THE ANTI-INFLAMMATORY EFFECTS OF CALENDULA OFFICINALIS EXTRACT ON EXPERIMENTAL ANIMALS
Authors: Kumar Ranjeet , Zilate Sarju R , Varma Sushil , Kumari Sweety 
Published: May 2019

Introduction: Calendula officinalis is one of those plants which have medicinal importance due to its flowers has pharmacological activity the important pharmacological parameters have been less investigated properly and can be scientifically proved by reverse pharmacology. It was found of interest to evaluate these properties of extract of flowers of Calendula officinalis scientifically in experimental models.
Methods: Study was conducted in Albino Wistar rats.Fresh Calendula officinalis flowers were collected, extraction and drug formulation was made. Anti-inflammatory activity of hydroalcoholic extract of Calendula officinalis (HECO) flowers was studied in the Carrageenan induced paw edema model & Cotton pellet induced granuloma models The differences between experimental groups were compared by ANOVA followed by Students “t” unpaired test.
Results: The Calendula officinalis extract of flowers at 200 and 400 mg/kg showed significant and highly significant inhibition (p< 0.05 and p<0.001, respectively) of paw edema after giving the carrageenan in the rat paw in comparison of control. In cotton pellets induced granuloma pouch method also, the Hydrochloric extract of Calendula officinalis (HECO) flowers showed very significant reduction of weight of granuloma (p<0.01) with 22.80% protection as compared with control.
Conclusion: We conclude that the Anti-inflammatory activity was noted with Hydrochloric extract of Calendula officinalis in a dose-dependent manner in acute (carrageenan-induced hind paw edema model) as well as sub-acute (cotton pellet induced granuloma model) inflammatory experimental models. They decrease the chemical mediators of inflammation
Key Words: Calendula Officinalis, anti inflammation, Paw Edema Model, granuloma pouch method , HECO
Special Aspects of Fixing Interfering Source Located in Close Proximity to Radio-Electronic Equipment with Multi-Channel Receiver and Estimate of Accuracy
Authors: Borovikov S. G. , Ivensky A. A. 
Published: May 2019

One of the fundamental properties of modern radio electronic equipment (REE) is jammer-induced performance in particular when located near REE, when they significantly affect the parameters of electromagnetic field generated and/or received by REE. One of the ways of antijamming is its rapid detection by REE for elimination purpose. In solving this problem, both the minimum detection time and the accuracy of the noise source location are equally important. In this article, the problem is considered using the example of radar detection with a multi-channel receiving device and thrown noise transmitter located close to its antenna field. The schemes displaying the problem geometry for phase and difference-distance-measuring methods for determining of jammer position are presented. Expressions are formed that determine the area of uncertainty zone when jammer detecting and connection of this value with radar parameters – ranging and azimuth accuracy. The necessity of using expressions free of far zones assumptions with respect to the radar and jammer relative position is explained. Ranging based on the signal received by radar in the mode of circular or sector review is considered. The results obtained confirm the necessity to take into account the distance between the jammer and REE when implementing the basic methods for determining radiation source location.