bluuebunny/crossref_metadata_2025_split huggingface dataset:
ANALISIS PERFORMA HEAT EXCHANGER DENGAN VARIASI ARAH ALIRAN DAN PENAMBAHAN VORTEX GENERATOR UNTUK MENGATASI ICING PADA KARBURATOR PESAWAT PISTON ENGINE
Authors: Rahayu Geroda Lucia , Kasmara Joni , Marausna Gaguk 
Published: July 2022

Pesawat merupakan alat transportasi yang pada saat ini populer digunakan oleh masyarakat. Salah satu gangguan yang sering terjadi yaitu hujan dan cuaca buruk, hal ini menyebabkan temperatur dan tekanan di setiap lingkungan berbeda dan akan mengakibatkan terbentuknya lapisan es pada komponen pesawat. Pada pesawat piston engine, terdapat beberapa komponen salah satunya yaitu karburator, yang berfungsi mencampurkan udara dan fuel. Dengan ini, dibutuhkan adanya anti icing guna mencegah terjadinya icing pada karburator.Metode yang digunakan adalah metode experimental dengan membuat prototype untuk mensimulasikan heat exchanger, dengan memanfaatkan gas buang yang berasal dari mesin geset guna mengatasi icing (drop late) pada karburator khususnya pada pesawat piston engine. Variasi arah aliran dan penambahan vortex generator twisted type pada penelitian ini yaitu aliran paralel dan aliran counter tanpa dan dengan penambahan vortex generator.Hasil penelitian menunjukan bahwa variasi arah aliran tanpa dan dengan penambahan vortex generator twisted insert type di dalam pipa konsentrik. Pada aliran paralel tanpa vortex generator twisted insert type memiliki nilai perpindahan kalor konveksi sebesar 337,8 W dan nilai efektifitas sebesar 66,3%, sedangkan pada aliran counter tanpa vortex generator twisted insert type memiliki nilai perpindahan kalor konveksi sebesar 316,6 W dan nilai efektifitas sebesar 67,2%. Sebaliknya aliran paralel dengan penambahan vortex generator twisted insert type memiliki nilai perpindahan kalor konveksi sebesar 340,8 W, nilai pressure drop sebesar 17,6 Pa, dan nilai efektivitas sebesar 71,5%. Sedangkan aliran counter dengan penambahan vortex generator twisted insert type memiliki nilai perpindahan kalor konveksi sebesar 435,4 W, nilai pressure drop sebesar 21,1 Pa, dan nilai efektivitas sebesar 74,6%. Dari penelitian ini dapat disimpulkan bahwa variasi arah aliran tanpa dan dengan penambahan vortex generator twisted insert type dapat mempengaruhi peningkatan nilai perpindahan kalor konveksi menyeluruh (Q), pressure drop (DP) dan nilai efektivitas (e) pada heat exchanger.
ANALISIS RISER TERHADAP PENGECORAN PROPELLER DENGAN ALUMINIUM BEKAS
Authors: Wicaksono Dhimas 
Published: July 2022

Riser merupakan saluran yang berfungsi sebagai pensuplai cairan pada saat coran mengalami penyusutan dan juga sebagai lubang keluarnya udara-udara yang terjebak dalam rongga cetakan. Pemanfaat Kualitas produk pengecoran salah satunya dipengaruhi oleh sistem konstruksi saluran penambah/Riser yang merupakan metode alternative pengembangan industry pengecoran di Indonesia. Propeller merupakan salah satu produk hasil yang sangat dibutuhkan di sector otomotif Dirgantara. Untuk dapat meminimalkan biaya produksi, penulis mengguanakan bahan baku aluminium bekas yang sering digunakan pada sector industri di Indonesia. Penelitian ini bertujuan untuk mengetahui pengaruh saluran penambahan Riser terhadap kekerasan, porositas serta Penyusutan hasil pengecoran Propeller yang menggunakan bahan aluminium bekas.
Penelitian dilakukan dengan membuat 3 variasi Riser berbentuk tabung dengan variasi A tidak menggunakan Riser dan variasi ke B dan C menggunakan diameter 7 mm dan 15 mm dengan panjang 10 mm dengan bahan baku pengecoran aluminium bekas (daur ulang) pada temperature tuang 7000 C. Berdasarkan hasil pengujian untuk komposisi kimia aluminium daur ulang terkandung paduan (Al) 90.60% dan (Si) 4.51%. Nilai persentase penyusutan untuk variasi A sebesar 3,88%, untuk variasi B sebesar 2,59%, dan untuk variasi C sebesar 2,02%. Hasil penelitian penyusutan menunjukan bahwa semakin besar Riser maka semakin kecil tingkat penyusutannya. Pada pengujian struktur mikro dapat diambil kesimpulan bahwa 3 variasi memiliki pengaruh pada tingkat porositas yang mana Pada variasi (A) memperlihatkan cacat yang nampak dan memiliki ukuran yang cukup besar dan luas. Sedangkan variasi (B) memperlihatkan cacat cor dimana ukuran cacat relatif lebih kecil apabila dibandingkan dengan variasi (A) akan tetapi pada pengujian kekerasan, variasi Riser tidak siginifikan mempengaruhi tingkat kekerasan aluminium bekas tetapi sangat berpengaruh pada tingkat penyusutan dan porositas specimen.
ANALISIS EFEKTIVITAS TURN AROUND TIME DENGAN METODE CRITICAL PATH METHOD PADA AKTIVITAS PERAWATAN C05- CHECK PESAWAT AIRBUS 320-200
Authors: Setiawan Ferry , Sofyan Edi , Romadhon Faisal 
Published: July 2022

Penelitian ini bertujuan untuk meningkatkan efektivitas pelaksanaan suatu aktivitas perawatan sesuai dengan task card C05-Check Pesawat Airbus 320-200, sehingga dihasilkan aktivitas perawatan yang lebih efektive terhadap jumlah waktu yang dibutuhkan dalam mengerjakan sebuah tugas kerja dari mulai awal perawatan sampai selesai atau sering di sebut Turn Around Time (TAT). Permasalahan TAT pada aktivitas perawatan C05-Check Airbus 320-200 adalah waktu TAT yang cukup lama sehingga membutuhkan biaya operasional teknisi yang cukup besar, dan adanya kerugian karena waktu tunggu operasinal pesawat pada saat perawatan. TAT pada aktivitas perawatan C05-Check Pesawat Airbus 320-200 dengan jumplah 351 task card, selama ini masih memakai standart perusahaan yang di hitung dengan metoda giant chart yaitu selama 13 hari kerja.
Permasalahan yang ada mendorong penulis melakukan analisis dan perhitungan TAT pada aktivitas perawatan C05-Check Pesawat Airbus 320-200 dengan metode Critical Path Method (CPM), sebuah metode yang digunakan untuk mengidentifikasi tugas-tugas yang ada dalam sebuah aktivitas pekerjaan dan membentuk desain jaringan CPM sesuai dengan urutan dan jalur kritis pekerjaan.
Hasil perhitungan Turn Around Time dengan metode (CPM) pada aktivitas perawatan C05-Check Pesawat Airbus 320-200 dengan jumlah task card 315 adalah 10,46 hari kerja, dengan jalur kritis berada pada code aktivity A-B-D-D1-D2-D3-D4-D5-D6-D7-H-I-J, pekerjaan secara seri code aktivity A-B-H-I-J, Sedangkan pekerjaan code aktivity C-D-E-F-G. Desian jarring CPM ini menghasilkan waktu perawatan yang lebih sedikit jika di bandingkan TAT standart Perusahaan yaitu 13 hari kerja. Selisih waktu penyelesaian TAT dengan metode CPM dengan Standart perusahanan adalah 2,54 hari kerja, sehingga dapat di simpulkan bahwa TAT dengan perhitungan CPM lebih efektif pada aktivitas perawatan C05-Check Air Bus 320 - 200.
PENGARUH PEMANASAN AWAL TERHADAP SIFAT MEKANIK SAMBUNGAN SPOT FRICTION STIR WELDING DALAM PEMASANGAN RIVET ALUMUNIUM 2024
Authors: Prasetyo Koesgi Dicky , Sehono  , Wicaksono Dhimas 
Published: July 2022

Teknik pengelasan pada aluminium sangat perlu dikembangkan dikarenakan penggunaannya dalam bidang manufaktur sangatlah dibutuhkan khususnya aluminium 2024 yang digunakan pada penelitian ini. Logam jenis aluminium ini memiliki peranan penting pada industri manufaktur pesawat dan otomotif hal tersebut dapat perhatikan dari hampir seluruh rangka dan skin menggunakan aluminium. Selain itu metode penggabungan dua bahan material saat ini juga banyak yang sama namun banyak yang belum sesuai dengan karakteristik material yang berbeda. Tujuan dari penelitian ini adalah untuk mengetahui perubahan nilai kekuatan tarik pada paduan aluminium dengan pengelasan FSW tanpa pemanas dan pengelasan FSW dengan tambahan pemanas (transient thermal). Metode Penelitian dilakukan dengan pengelasan paduan aluminium plat 2024-T3 menggunakan teknik FSW tanpa pemanas dan teknik FSW dengan perlakuan transient thermal. Metode pengumpulan data yang akan digunakan untuk penelitian ini adalah dengan metode eksperimen, pada penelitian ini menggunakan alumunium seri Aluminum 2024-T3: skin dan doubler. Sebelum proses pengeboran terjadi untuk penggabungan aluminium pemanasan awal dilakukan pada plat menggunakan heater dengan variasi temperatur 100℃, 150℃, dan 200℃. Kemudian saat proses pengeboran dilakukan, kecepatan putar yang di gunakan adalah 1350 rpm, kecepatan tersebut di ambil berdasarkan peneliti sebelumnya dikarenakan penggabungan material dengan nilai tersebut merupakan yang terbaik. Proses riveting dilakukan setelah pengeboran (welding) menggunakan paku keling. Peningkatan temperatur pada spesimen menyebabkan sifat mekanik yang cenderung meningkat pada tiap-tiap temperatur 100℃, 150℃, dan 200℃ yang di uji coba pada kekuatan geser pada spesimen. Hasil pengujian kekuatan geser yang terbaik pada temperatur 150℃ dengan nilai sebesar 16,87 MPa. Uji kekerasan terbaik pada temperatur 200℃ dengan nilai 287,52 kg/mm. Hal ini disebabkan karena munculnya pada struktur mikro dan hilangnya efek tempa dari panas yang dihasilkan dalam proses friction stir welding. Pengujian kekerasan menunjukkan bahwa nilai kekerasan dari tiap spesimen hasil dengan metode friction stir welding semakin menurun.. Namun penurunan nilai kekerasan yang terjadi tidaklah sangat signifikan. Penurunan nilai kekerasan ini dikarenakan sifat material aluminium 2024 yang telah mengalami strain hardened temper di mana adanya panas yang cukup tinggi akan membuat rekristalisasi pada material spesimen.
STUDI EKSPERIMENTAL KARAKTERISTIK PERPINDAHAN KALOR PADA PIPA KONSENTRIK DENGAN TWISTED TAPE INSERT WITH VARIABEL WIRE COIL UNTUK MENGATASI ICING CONTAMINATED TAIL STALL
Authors: Purwanto Rivaldy , Marausna Gaguk , Jayadi Farid 
Published: July 2022

Horizontal stabilizer adalah komponen yang sangat penting pada pesawat terbang, dimana digunakan untuk mengontrol sikap pesawat pada saat terbang. Metode penelitian ini adalah metode eksperimen dengan twisted tape insert with variabel wire coil dimana untuk memanfaatkan gas panas dengan memanfaatkan perpindahan kalor dengan spesimen yang juga berbeda untuk mencegah horizontal stabilizer dari adanya icing. Hasil penelitian ini adalah metode eksperimen twisted tape insert with variabel wire coil dapat memanfaatkan gas panas untuk mencegah terjadinya icing pada horizontal stabilizer. Penelitian ini membandingkan perpindahan kalor yang paling baik dengan nilai 56,000 W, dan meningkat juga koefisien perpindahan kalor konveksi 16,44 W/m2˚C, dan faktor gesekan 0,041, pressure drop (ΔP), 2,65 Pa.
Postdate antenatal testing
Authors: Ohel G. , Yaacobi N. , Linder N. , Younis J. 
Published: July 2002

AbstractObjective: To test the effect on pregnancy outcome of a policy of very early commencement of postdate surveillance testing, and induction of labor at 42 weeks. Methods: Retrospective analysis of 2776 consecutive cephalic deliveries at 38–42 weeks of gestation. Management of the postdate pregnancies included twice‐weekly antenatal testing beginning at 40 completed weeks and elective induction of labor at 42 completed weeks. Pregnancy outcome parameters were compared between the groups delivered at 38–40 weeks and at 41–42 weeks. Results: There were 2138 pregnancies delivered at 38–40 weeks and 638 at 41–42 weeks. The latter group had a statistically significant increase in the rate of cesarean section, mainly accounted for by an increased rate of fetal distress and failure to progress in labor. Similarly the rate of instrumental vaginal delivery, meconium in labor and macrosomia had a statistically significantly higher incidence in the postdate group. These differences in outcome were already apparent at 41 weeks of gestation. Conclusion: Despite early initiation of fetal surveillance, starting at 40 completed weeks, postdate pregnancies are associated with an increased rate of emergency cesarean section, macrosomia and meconium in labor.
Differential alterations of NF‐κB to oxidative stress in primary basal forebrain cultures
Authors: Gu Zezong , Cain Lisa , Werrbach‐Perez K. , Perez‐Polo J.Regino 
Published: July 2002

AbstractOxidative stress has been linked to neuronal cell death resulting from either acute insults due to ischemia, trauma, excitotoxicity, or chronic neurodegenerative diseases. Cholinergic basal forebrain neurons (CBFNs) compete for nerve growth factor (NGF) synthesized in the hippocampus and cortex via retrograde transport. NGF affects CBFN survival and cholinergic function via activation of the NF‐κB transcription factor and this signaling pathway appears to be impaired in aged rats. Here, we demonstrate that activation of NF‐κB in basal forebrain primary culture via treatment with hydrogen peroxide or TNF‐alpha is predominantly restricted to CBFNs, and that NF‐κB activation appears to mostly affect p65 translocation to the nucleus, but not the p50 subunit. These results are consistent with NF‐κB activation being a part of recovery processes after acute oxidative stress. Since p50 or p49 (also called p52) binding to promoter sites does not stimulate transcription — both p50 and p49 lack an activating domain — and p65 does contain an activating domain and thus can act as a transcription enhancer, differential translocation of different NF‐κB dimers can act as repressors of constitutive activity or enhancers. These results are in agreement with the hypothesis that p50/p65 is the active trans‐activating species of NF‐κB, as compared to p50/p50 homodimers which bind to NF‐κB binding sites but do not trans‐activate promoters. Our results also suggest that selective activation of different NF‐κB dimer species may have regulatory significance in neuronal responses to acute or chronic insults to CNS. Thus, increased p65 translocation could have enhancing effects while increased p50 translocation could have a repressor role. Manipulation of the types of NF‐κB species being translocated could provide a basis for therapeutic strategies.
Characterization of Polycationic Amino Acids Fusion Systems for Ion‐Exchange Purification of Cyclodextrin Glycosyltransferase from Recombinant Escherichiacoli
Authors: Kweon Dae‐Hyuk , Lee Dae‐Hee , Han Nam‐Soo , Rha Chan‐Su , Seo Jin‐Ho 
Published: July 2002

AbstractFusion proteins with charged polycationic amino acid tails were constructed for the purpose of simple ion‐exchange purification with high purity. A number of positively charged lysine and arginine tails were fused to the C‐terminus of cyclodextrin glycosyltransferase (CGTase) derived from Bacillus macerans and expressed in Escherichia coli. The ionic binding forces provided by the tails allowed the selective recovery of CGTase from recombinant E. coli cell extracts, while CGTase by itself could not bind to the cation exchanger at neutral pH. The type of amino acids used and the length of the tail directly affected the purification factors. Most intracellular proteins of E. coli adsorbed on the cation exchanger could be removed by washing with 400 mM NaCl solution at pH 7.4, suggesting that a fusion partner suitable for purification purpose should be provided with high binding strength and the maintenance of adsorption by washing with NaCl solution. Among the fusion CGTases constructed, the CGTK10ase containing 10 lysine residues provided sufficiently high binding strength to allow purification to its homogeneity through simple ion‐exchange chromatography.
Biological Verification of Fluid‐to‐Particle Interfacial Heat Transfer Coefficients in a Pilot Scale Holding Tube Simulator
Authors: Ramaswamy H. S. , Awuah G. B. , Simpson B. K. 
Published: July 2002

AbstractInactivation kinetics of immobilized bovine pancreas trypsin (type III) was used in conjunction with a finite difference model to verify fluid‐to‐particle heat transfer coefficients to particulates in a holding tube of a pilot scale aseptic processing simulator operated at temperatures ranging from 90 and 110 °C. The enzyme was sealed in a stainless steel capsule, which was pretested to be suitable for high‐temperature, short‐time applications, and embedded at the center of a finite cylindrical particle. The percentage retention of the enzyme activity was calculated by using transient temperatures and their respective D values in a finite difference program. Heat transfer coefficients estimated for the potato particles under similar experimental conditions were used as input data. Excellent comparison was observed between predicted and measured percentage retention of enzyme activity.
Protein Adsorption Characteristics of a Sulfonic‐Acid‐Group‐Containing Nonwoven Fabric
Authors: Kim Min , Sasaki Masami , Saito Kyoichi , Sugita Kazuyuki , Sugo Takanobu 
Published: July 2002

AbstractA sulfonic acid (SO3H)‐group‐containing nonwoven fabric was prepared by radiation‐induced graft polymerizaton of an epoxy‐group‐containing monomer, glycidyl methacrylate, onto a nonwoven fabric and subsequent sulfonation. The nonwoven fabric containing SO3H groups at different densities was equilibrated with lysozyme in a buffer (pH 6.0). The equilibrium binding capacity (EBC) of lysozyme increased linearly with increasing SO3H group density. The SO3H‐group‐containing polymer chains extended from the pore surface due to mutual electrostatic repulsion and held lysozyme in multilayers. The maximum EBC was 0.7 kg/kg at a SO3H group density of 1.7 mol/kg.
Immunogenicity of malaria transmission‐blocking vaccine candidate, y230.CA14 following crosslinking in the presence of tetanus toxoid
Authors: Vincent Arokia A. , Fanning Sarah , Caira Francesco C. , Williamson Kim C. 
Published: July 2002

SUMMARYProteolytically processed 310 kDa form of Plasmodium falciparum gamete surface antigen, Pfs230, is the target of malaria transmission‐blocking monoclonal antibodies. To design a recombinant malaria transmission‐blocking subunit vaccine, the amino terminus of the 310 kDa surface‐exposed form of Pfs230 was mapped to amino acids (aa) 522 and 584 using a series of peptides and recombinant proteins encoding distinct regions of Pfs230. Antiserum generated against an Escherichia coli‐produced recombinant protein, spanning the Pfs230 processing site and extending into the cysteine domains, r230/MBP.C (aa 443–1132), reduced parasite infectivity by 71.2–89.8%. To determine if the region spanning the cleavage site blocked malaria transmission when produced as a secreted protein by Saccharomyces cerevisiae, y230.CA14 (aa 467–584) was generated, purified, emulsified in adjuvant and used to vaccinate mice. In contrast to E. coli‐produced r230/MBP.C, the immune response generated against y230.CA14 was very weak. To enhance the response, y230.CA14 was mixed with tetanus toxoid, chemically crosslinked, repurifed, and its immunogenicty compared with unconjugated y230.CA14. Conjugated‐y230.CA14/TT required fewer booster injections to induce an immune response against Pfs230 and the antibodies generated reacted with the surface of intact gametes and immunoprecipitated radiolabelled Pfs230 extracted from 125I surface‐labelled gametes to a greater extent. After seven injections, all y230.CA14 vaccinated mice developed anti‐Pfs230 antibodies and the isotype profile was the same. In addition to enhancing the initial immune response generated against y230.CA14, conjugation focuses the immune response toward epitopes within the region of Pfs230 present on the surface of the gamete.
ADULT SOFT TISSUE SARCOMA
Authors: Bruce Mann G. , Lewis Jonathan J. , Brennan Murray F. 
Published: July 2002

Background: Soft tissue sarcomas (STS) are a group of anatomically and histologically diverse tumours. They account for about 1% of adult malignancies, and about 50% of patients diagnosed with sarcoma eventually die of the disease. These tumours are grouped together because of shared biological characteristics and treatment responses. Methods: A review of the key literature on STS was undertaken, complemented by data taken from the prospectively accumulated database of 3442 patients treated for STS at Memorial Sloan‐Kettering Cancer Center (MSKCC) from July 1982 to December 1997. Results: Despite advances in knowledge of the molecular genetics of STS, the aetiology in most cases remains elusive. Management has been gradually refined over the last two decades. Core biopsy usually provides enough material for diagnosis. Computed tomography and magnetic resonance imaging provide a similar amount of information, which is usually adequate for surgical planning. Amputation as standard treatment for extremity lesions has been replaced by limb‐sparing surgery in about 90% of patients. The role of adjuvant radiation has been further defined: it has been shown to be unnecessary for completely excised tumours less than 5 cm in diameter, but effective in decreasing local recurrence for others. Adjuvant chemotherapy has been controversial for many years. Recent meta‐analysis of randomized trial results has found a small reduction in local and distant relapse, and a trend to better overall survival. Recurrent or metastatic disease should be completely excised if possible. Conclusions: Soft tissue sarcoma requires multidisciplinary care tailored to the individual patient and tumour for optimal results.
Dose perturbation by air cavities in megavoltage photon beams: Implications for cavity surface doses
Authors: Ebert Martin A , Spry Nigel A 
Published: July 2002

SUMMARYGas‐filled cavities in the body are known to perturb megavoltage photon beams in radiation therapy. The bowel represents one such cavity where cavity dimensions can vary throughout a treatment course. This has implications for doses to the surface of the bowel. Doses to the first 0.1 mm and 1.0 mm of cavity surfaces were calculated for 6 MV and 18 MV photon beams for a range of cavity sizes. It is found that relatively minor variations in cavity surface doses result over the typical range of rectal cavity size (2–3 cm). However, the variations in surface dose should be considered whenever bowel reactions must be considered, or when the target cells of interest line the bowel itself.
Bacterial endocarditis in neonatal intensive care
Authors: Drew GF OPIE, SH FRASER, JH , Drew S 
Published: July 2002

Objectives: To ascertain the incidence of bacterial endocarditis in a level III neonatal nursery. To document the clinical features, assess survival, and evaluate the role of central venous catheters in neonates with bacterial endocarditis.Methodology: Index cases were identified by retrospective review of the echocardiographic records of infants admitted to the neonatal nursery from 1983 to 1995. Data obtained by review of the clinical records of these infants, and case‐matched controls.Results: From January 1983 to December 1995, 12 249 infants were admitted to the Special Care Nursery. Eight infants with endocarditis were identified, an incidence of 0.07%. Presenting symptoms and signs were often vague and nonspecific. Gestation less than 32 weeks, birthweight less than 1500 g, thrombocytopenia and neutropenia or neutrophilia were common features. Infants with endocarditis had a significantly higher Clinical Risk Index for Babies score than those without endocarditis. The tricuspid valve was involved in seven infants, six of whom had a percutaneous central venous catheter in situ before diagnosis. Mitral valve involvement occurred in two infants, neither of whom had central lines inserted. However, compared to infants without endocarditis, the placement of a central venous line was not of statistical significance. Seven of the eight infants survived following prolonged antibiotic therapy.Conclusions: Bacterial endocarditis is a rare but serious condition, which is usually not fatal. In the premature newborn infant, presenting signs and symptoms are often nonspecific. Endocarditis should therefore be considered in the unwell very low birthweight infant.