Experimental and numerical study on the influence of the laser hybrid parameters in partial penetration welding on the solidification cracking in the weld root

The aim of the present study is to investigate the influence of the laser hybrid welding parameters on the solidification cracks in the weld root for partial penetration welding. Welding trials were performed on thick-walled high-strength steels of grade S690QL under the same critical restraint intensity, with a variation of the welding velocity, wire feeding rate, and the focal position of the laser beam. It was ascertained that the welding velocity has a high impact on the solidification cracking phenomenon. A decrease in the welding speed leads to a reduction of the number of cracks in the weld root. The arc power has also a slight influence on the solidification cracking, while the change of the focal position of the laser beam shows also a remarkable effect. Besides, numerical simulation was performed to understand the thermomechanical behavior of the welds for different welding parameters to assist the interpretation of the experimental results.BMWi, 19582N, Investigation of the influence the restraint conditions on hot cracking in laser and laser-hybrid welding of thick structure steelsTU Berlin, Open-Access-Mittel - 202

Influence of an external applied AC magnetic field on the melt pool dynamics at high-power laser beam welding

The study deals with the determination of the influence of an externally applied oscillating magnetic field on the melt pool dynamics in high power laser beam and hybrid laser arc welding processes. An AC magnet was positioned under the workpiece which is generating an upward directed electromagnetic force to counteract the formation of the droplets. To visualise the melt flow characteristics, several experiments were carried out using a special technique with mild steel from S355J2 with a plate thickness of up to 20 mm and a quartz glass in butt configuration. The profile of the keyhole and the melt flow were recorded with a highspeed camera from the glass side. Additionally, the influence of the magnetic field orientation to the welding direction on the filler material dilution on laser hybrid welding was studied with variating oscillation frequency. The element distribution over the whole seam thickness was measured with X-ray fluorescence (XRF). The oscillation frequency demonstrated a great influence on the melt pool dynamics and the mixing of the elements of the filler wire. The highspeed recordings showed, under the influence of the magnetic field, that the melt is affected under strong vortex at the weld root, which also avoids the formation of droplets

Hybrid laser-arc welding of laser- and plasma-cut 20-mm-thick structural steels

It is already known that the laser beam welding (LBW) or hybrid laser-arc welding (HLAW) processes are sensitive to manufacturing tolerances such as gaps and misalignment of the edges, especially at welding of thick-walled steels due to its narrow beam diameter. Therefore, the joining parts preferably have to be milled. The study deals with the influence of the edge quality, the gap and the misalignment of edges on the weld seam quality of hybrid laser-arc welded 20-mm-thick structural steel plates which were prepared by laser and plasma cutting. Single-pass welds were conducted in butt joint configuration. An AC magnet was used as a contactless backing. It was positioned under the workpiece during the welding process to prevent sagging. The profile of the edges and the gap between the workpieces were measured before welding by a profile scanner or a digital camera, respectively. With a laser beam power of just 13.7 kW, the single-pass welds could be performed. A gap bridgeability up to 1 mm at laser-cut and 2 mm at plasma-cut samples could be reached respectively. Furthermore, a misalignment of the edges up to 2 mm could be welded in a single pass. The new findings may eliminate the need for cost and time-consuming preparation of the edges

The bulging effect and its relevance in high power laser beam welding

The present work deals with the recently confirmed widening of the weld pool interface, known as a bulging effect, and its relevance in high power laser beam welding. A combined experimental and numerical approach is utilized to study the influence of the bulge on the hot cracking formation and the transport of alloying elements in the molten pool. A technique using a quartz glass, a direct-diode laser illumination, a high-speed camera, and an infrared camera is applied to visualize the weld pool geometry in the longitudinal section. The study examines the relevance of the bulging effect on both, partial and complete penetration, as well as for different sheet thicknesses ranging from 8 mm to 25 mm. The numerical analysis shows that the formation of a bulge region is highly dependent on the penetration depth and occurs more frequently during partial penetration above 6 mm and complete penetration above 8 mm penetration depth, respectively. The location of the bulge correlates strongly with the cracking location. The obtained experimental and numerical results reveal that the bulging effect increases the hot cracking susceptibility and limits the transfer of alloying elements from the top of the weld pool to the weld root.DFG, 411393804, Experimentelle und numerische Untersuchung der Entstehungsmechanismen des Bulgings und dessen Einfluss auf die Bildung von Mittelrippendefekten beim Hochleistungslaserstrahlschweißen niedriglegierter Stähle hoher BlechdickeDFG, 416014189, Simulation des Einflusses der elektromagnetisch unterstützten Durchmischung beim Laserstrahlschweißen dickwandiger Stahlbauteile mit Zusatzmateria

Dokuz Tip Mizaç Ölçeği Ergen (DTMÖ-E) Formunun Geçerlik- Güvenirliği ve Ergenlerde Dikkat Eksikliği Hiperaktivite Bozukluğu İle Mizaç Tipleri Arasındaki İlişki

The purpose of this study is developing adolescent form (11-16 years old) of Nine Types Temperament Scale (NTTS) depending on Nine Types Temperament Model (Study 1) and evaluating and searching the relationship between Attention Deficit and Hyperactivity Disorder (ADHD) and Types of NTTM (Study 2). Sample of Study I consist of 1240 students who are between 11 and 16 years old. Pilot form of the Scale which consists of 90 items is tested with confirmatory factor analysis and with convergent and discriminant validity and the last version of the measure which consist of 82 items is prepared. Basic Personality Traits Inventory (BPTI) which depends on Fife Factor Model is used for Criterion-related validation. Results show that NTTS-A is valid and reliable measure for evaluating temperament types between 11-16 years adolescents. Their fit index is calculated as χ2 /df <3; SRMR, 0.06; RMSEA, 0.045; CFI, 0.909: TLI, 0901 supported to validity data. Sample of Study II consist of 56 adolescents who are diagnosed with ADHD according to DSM-IV diagnosis criteria and 56 students who does not get diagnosed with ADHD or mental retardation/medical disorder. Temperament types of participants are evaluated by the agency of Study-I and NTTS-A, which is developed appropriate for Turkish culture. Indication of the study shows that there are more NTT7 and NTT8 in NTTM types between adolescents with ADHD than the group, who are not diagnosed with ADHD. As a result, it is discussed that traits which belong to some temperament types could have a predisposing effect on emergence of ADHD, experiencing these traits extreme severely could cause a view similar to ADHD and ADHD which is a neurodevelopmental disease could interact with temperament traits of person, in that way it could illustrate ADHD clinic. Available findings support critics about that students are labelled as ADHD specially in the last years in education environment even if they have mostly not developmental problems and students are diagnosed easily with limited observations. However, it is asserted that diagnosis based on temperament, treatment and psychosocial support programmes could be formed and effects of ADHD, which is a factor interacting with temperament traits, on personality structure of adolescents on their development process, could be predicted. Our study has the feature of being the first measure developing study which is intended to evaluate temperament types of adolescents between 11-16 years old and also it is has the feature of being the first study which searches relationship between NTTM types and ADHD.Bu çalışmanın amacı, Dokuz Tip Mizaç Modeli (DTMM)’ne dayalı olarak erişkinler için geliştirilen Dokuz Tip Mizaç Ölçeğinin (DTMÖ) 11-16 yaş arası ergen formunu (DTMÖ-E) geliştirmek (Çalışma I) ve DTMM tipleri ile Dikkat Eksikliği Hiperaktivite Bozukluğu (DEHB) arasındaki ilişkiyi incelemek ve değerlendirmektir (Çalışma II). Çalışma I’in örneklemi 11-16 yaş aralığındaki 1240 öğrenciden oluşmaktadır. 90 maddeden oluşan ölçeğin pilot formu doğrulayıcı faktör analizi, yakınsak ve ayırma (diskriminant) geçerliği ile test edilmiş ve ölçeğin 82 maddelik son hali hazırlanmıştır. Ölçüt geçerliği için ise Beş Faktör Modeli’ne dayanan Temel Kişilik Özellikleri Envanteri (TKÖE) kullanılmıştır. Sonuçlar, DTMÖ-E’nin 11-16 yaş arası ergenlerin mizaç tiplerini değerlendirmede kullanılabilecek geçerli ve güvenilir bir ölçek olduğunu göstermektedir. Uyum indeksleri χ2 /df <3; SRMR, 0.06; RMSEA, 0.045; CFI, 0.909: TLI, 0901 olarak geçerlik verilerini destekler nitelikte hesaplanmıştır. Çalışma II’nin örneklemi ise DSM-IV tanı ölçütlerine göre DEHB tanısı almış 56 ergen ve mental retardasyon / tıbbi rahatsızlık ve DEHB tanısı bulunmayan 56 öğrenciden oluşmaktadır. Katılımcıların mizaç tipleri, Çalışma-I ile Türk kültürüne uygun olarak geliştirilen DTMÖ-E aracılığıyla değerlendirilmiştir. Çalışmanın bulguları, DEHB’li ergenler arasında DTMM tiplerinden DTM7 ve DTM8’in DEHB tanısı almayan gruba göre daha fazla bulunduğunu göstermektedir. Sonuç olarak, bazı mizaç tiplerine ait özelliklerin DEHB ortaya çıkmasına yatkınlaştırıcı etkisinin olabileceği, bu özelliklerin aşırı şiddette yaşanmasının DEHB benzeri bir görünüm ortaya çıkarabileceği ve nörogelişimsel bir hastalık olan DEHB’in kişinin mizaç özellikleri ile etkileşerek DEHB kliniğini sergileyebileceği tartışılmıştır. Mevcut bulgular, eğitim çevrelerinde öğrencilerin özellikle son yıllarda sıklıkla gelişimsel bir sorun olmadığı halde DEHB olarak etiketlenmesi ve sınırlı gözlemlerle kolay tanı konmasıyla ilgili eleştirileri destekleyebilecek niteliktedir. Bunun yanı sıra DTMM’nin yaklaşımı sayesinde mizaç temelli tanı, tedavi ve psikososyal destek programlarının oluşturulabileceği ve mizaç özellikleriyle etkileşen bir faktör olarak DEHB’in ergenlerin gelişim süreçlerinde kişilik yapısına nasıl bir etkide bulunacağının öngörülebileceği öne sürülmektedir. Çalışmamız, Türkiye’de 11-16 yaş arasındaki ergenlerin mizaç tiplerini değerlendirmeye yönelik ilk ölçek geliştirme çalışması olmanın yanı sıra, DTMM tipleri ile DEHB arasındaki ilişkiyi inceleyen ilk çalışma olma özelliğindedir

Evaluation of Consultations Requested from Patients Admitted to the Emergency Department

Aim: This study was aimed to conduct an investigation towards evaluation of the efficiency of the consultation system that is in place in the emergency service of our hospital and identification and correction of deficiencies in this system. Materials and Methods: Patients who were admitted to the emergency department and for whom requesting a consultation were required for any reason were included in the study. Forms were filled out by the emergency research assistants. Patients whose data was incomplete and consents could not be obtained were excluded from the study.Results: A total of 213 patients were included in the study, and a total of 315 consultations were requested. The total number of consultations requested by the internal medicine departments was 126, and the total number of consultations requested by the trauma (surgery) departments was 189. Of the 213 patients, 104 (48.8%) were hospitalized and 109 (51.2%) were discharged. The average number of consultations of 213 patients was 1.5±0.7, the average length of stay of the patients in the emergency service was 366.7±312.9 min. and the mean age of the patients was 41±24 years. The average seniority of the consultant physicians in a total of 315 consultations performed was 26.8±10.6 months, and the average consultation response time of the consultant physicians was 62.2±67.8 min. Conclusion: Because of the changing healthcare system in our country, the consultation services, particularly in university hospitals, should be re-structuredAim: This study was aimed to conduct an investigation towards evaluation of the efficiency of the consultation system that is in place in the emergency service of our hospital and identification and correction of deficiencies in this system. Materials and Methods: Patients who were admitted to the emergency department and for whom requesting a consultation were required for any reason were included in the study. Forms were filled out by the emergency research assistants. Patients whose data was incomplete and consents could not be obtained were excluded from the study.Results: A total of 213 patients were included in the study, and a total of 315 consultations were requested. The total number of consultations requested by the internal medicine departments was 126, and the total number of consultations requested by the trauma (surgery) departments was 189. Of the 213 patients, 104 (48.8%) were hospitalized and 109 (51.2%) were discharged. The average number of consultations of 213 patients was 1.5±0.7, the average length of stay of the patients in the emergency service was 366.7±312.9 min. and the mean age of the patients was 41±24 years. The average seniority of the consultant physicians in a total of 315 consultations performed was 26.8±10.6 months, and the average consultation response time of the consultant physicians was 62.2±67.8 min. Conclusion: Because of the changing healthcare system in our country, the consultation services, particularly in university hospitals, should be re-structure

Improvement of Filler Wire Dilution Using External Oscillating Magnetic Field at Full Penetration Hybrid Laser-Arc Welding of Thick Materials

Hybrid laser-arc welding offers many advantages, such as deep penetration, good gap bridge-ability, and low distortion due to reduced heat input. The filler wire which is supplied to the process is used to influence the microstructure and mechanical properties of the weld seam. A typical problem in deep penetration high-power laser beam welding with filler wire and hybrid laser-arc welding is an insufficient mixing of filler material in the weld pool, leading to a non-uniform element distribution in the seam. In this study, oscillating magnetic fields were used to form a non-conservative component of the Lorentz force in the weld pool to improve the element distribution over the entire thickness of the material. Full penetration hybrid laser-arc welds were performed on 20-mm-thick S355J2 steel plates with a nickel-based wire for different arrangements of the oscillating magnetic field. The Energy-dispersive X-ray spectroscopy (EDS) data for the distribution of two tracing elements (Ni and Cr) were used to analyze the homogeneity of dilution of the filler wire. With a 30° turn of the magnetic field to the welding direction, a radical improvement in the filler material distribution was demonstrated. This would lead to an improvement of the mechanical properties with the use of a suitable filler wire

Influence of oscillating magnetic field on the keyhole stability in deep penetration laser beam welding

The stability of the keyhole decreases for deep penetrated high-power laser beam welding. The keyhole tends to collapse with increasing laser power and e.g. keyhole induced porosity can occur. This study deals with the observation of the keyhole during high-power laser beam welding in partial penetration mode by means of a high-speed camera. A butt configuration of 25 mm thick structural steel and transparent quartz glass was used for the experiments. An oscillating magnetic field was applied perpendicular to the welding direction on the root side of the steel plate. The keyhole was highlighted with a coaxial diode laser. It was ascertained that the stability of the keyhole and the weld penetration depth were increased by applying an oscillating magnetic field with an oscillating frequency of 1.2 kHz and a magnetic flux density of 50 mT

Effect of microemulsion formulation on biodistribution of Tc-99m-Aprotinin in acute pancreatitis models induced rats

WOS: 000388750400045PubMed ID: 26923781Background: Aprotinin is a monomeric globular polypeptide, which derived from bovine lung tissue and theoretically attractive molecule in ameliorating the effects of acute pancreatitis. Acute pancreatitis is an inflammatory condition of the pancreas that is painful and at times deadly. Over the following two decades Aprotinin therapeutic potential on pancreatitis is proven experimentally, its clinical therapeutic success is limited due to low targeting to pancreas. Objective: The aim of this study was to evaluate the biodistribution of Technetium-(99m)(Tc-99m)Aprotinin solution (Tc-99m-Aprotinin-S) and Tc-99m-Aprotinin loaded microemulsion, which was prepared for the aim of treatment for acute pancreatitis. Method: Aprotinin was radiolabeled with Tc-99m. Radiochemical purity was determined with radioactive thin layer chromatography studies. Tc-99m-Aprotinin-S and Tc-99m-Aprotinin loaded microemulsion (Tc-99m-Aprotinin-M) was administered to acute edematous, severe necrotizing pancreatitis and air pouch model induced rats. Tissue distribution of Aprotinin was investigated with gamma scintigraphy and biodistribution studies. Results: Aprotinin was radiolabeled by Tc-99m with high radiochemical purity (95.430 +/- 0.946%). The complex was found to be stable at room temperature up to 6 h. Animal studies have shown that similar to that of other small proteins Aprotinin is accumulated primarily in the kidney. The scintigraphy and biodistribution studies showed that, while i. v. administration of (99m)TcAprotinin-S distributed mostly in kidneys and bladder, Tc-99m-Aprotinin-M, with droplet size of 64.550 +/- 3.217 nm, has high uptake in liver, spleen and pancreas. Conclusion: This might be concluding that microemulsions may be suggested as promising formulations for selectively targeting Aprotinin to pancreas inflammation.Scientific and Technological Research Council of Turkey (Tubitak) [108S083]; T.R. Prime Ministry State Planning Organization Foundation [09DPT001]The authors declare no conflict of interest. The authors alone are responsible for the content and writing of the article. This study was supported by The Scientific and Technological Research Council of Turkey (Tubitak 108S083). The authors also thank to the T.R. Prime Ministry State Planning Organization Foundation (Project Number: 09DPT001)