Sensor-integrated Tap Holder for Process Uncertainty Detection Based on Tool Vibration and Axial Length Compensation Sensors

The tapping process is one of the most widespread manufacturing processes for internal threads, usually carried out at the end of the value chain. Any non-compliance with required quality standards or even the destruction of the thread due to process uncertainty in the tapping process is therefore subjected to high rework costs. Possible process uncertainties in the tapping process can be triggered by synchronization errors between feed rate and spindle speed, axis offset, faulty core holes and wear of the tapping tool. In order to detect process uncertainties during tapping and thus provide a basis for initiating countermeasures, a sensor-integrated tap holder was developed. This paper presents the realized concept of a rotating telemetry unit for signal processing, data acquisition and wireless data transmitting via WiFi standard on basis of low-cost embedded systems. Furthermore, two unique sensor concepts for measuring close-to-tool vibrations and the axial length compensation of the tapping tool are shown. Based on the sensor data in combination with feature engineering methods, process uncertainty during tapping are detected

An experimental study on iron removal with ferric sludge recycling

An iron removal process, which makes use of the catalytic effect of ferric iron, is proposed. For this purpose, the reaction kinetics derived from the data of the batch experiments was applied to the continuous flow system. Based upon this reaction kinetics, it has been theoretically demonstrated that the volumes of aeration tanks can be significantly reduced by keeping a high concentration of ferric iron in the reactor. However, in natural waters, Fe(II) is found commonly to be in the range of 0.01-10 mg/l. These ferrous iron concentrations are not high enough to maintain the high concentrations of ferric iron in the aeration tank. Therefore, similar to the activated sludge processes used in wastewater treatment, it is suggested that the required Fe(III) concentrations can be maintained by recycling Fe(OH)3 sludge back to the aeration tank. It is known that the oxygenation of ferrous iron is catalyzed by the reaction product, ferric hydroxide. Catalytic action of the ferric iron sludges on the oxidation of ferrous iron by aeration has been identified and the kinetics of this catalytic reaction has been formulated by the authors. The oxidation of Fe(II) was studied in batch reactors in which the concentration of Fe(III) was in the range of 0-600 mg/l. The oxygenation rate increased linearly with the increasing Fe(III) concentrations up to 50 mg/l and a second-order polynomial relationship was found between the reaction rate and the Fe(III) concentrations in the range of 50-600 mg/l. The required volume (V) of the aeration tank and the effluent Fe(II) concentrations were determined as a function of the Fe(III) concentration. The volume of the aeration tank required for the same Fe(II) conversion was reduced by a factor of 15 when the Fe(III) concentration was raised from 0 to 600 mg/l at pH=6.7. No incremental benefit of the increase of Fe(III) concentration was observed at Fe(III) levels beyond the 600 mg/l. This study has experimentally demonstrated that significant savings can be achieved in iron removal systems by recirculating the Fe(III) sludges back to the aeration tank. An iron removal process that makes use of the catalytic effect of ferric iron is proposed. With this process, significant savings can be achieved in iron removal systems by recirculating the Fe(III) sludges back to the aeration tank

Students' and Teaching Staff's Assessments Regarding Distance Education Applications in Formal Education

Bu çalışma örgün eğitim içerisindeki uzaktan eğitim uygulamalarının öğrenci ve öğretim elemanı gözüyle değerlendirilmesi amacıyla yapılmıştır. Bu amaç doğrultusunda Türkiye'nin doğusunda yer alan bir üniversitede uzaktan eğitim ile ders veren beş öğretim elemanı ve bu üniversitede örgün eğitim görüp uzaktan eğitimle ders almakta olan altı öğrenci ile görüşmeler yapılmıştır. Çalışmada, örgün eğitim içerisindeki uzaktan eğitim uygulamalarında karşılaşılan problemleri daha bütünsel ve derinlemesine incelemek amaçlandığından nitel araştırma desenlerinden 'durum çalışması' yöntemi kullanılmıştır. Veriler içerik analizi ile incelenmiştir. Yapılan analizler sonucunda öğrencilerden elde edilen bulgular dört kategori altında 20 kod oluştururken öğretim elemanlarından elde edilen bulgular dört kategori altında 25 kod oluşturmuştur. Yapılan çalışmanın özellikle uzaktan eğitime geçmeyi düşünen ve yeni geçmiş olan eğitim kurumlarına yol göstereceği, bu konuda yaşanabilecek sıkıntılara yönelik önlemler almalarına imkân vereceği düşünülmektedir.The study was conducted with the aim of evaluating distance education applications in formal education from the viewpoints of students and teaching staff. Accordingly, five teaching staff offering distance learning courses at a university located in eastern part of Turkey were interviewed. Interviews were also made with six students who were enrolled in formal education at that university and were taking courses in distance format. In this study, 'case study' method as one of the qualitative research designs was used for a holistic and indepth examination of the problems encountered in distance education applications in formal education. Data were analyzed with content analysis. The findings related to students resulted in four categories with 20 codes falling under these categories. Similarly, the findings obtained from teaching staff yielded four categories with 25 codes under these categories. This study is considered to guide the educational institutions that are planning to adopt distance education or those that have just adopted distance education. It is also deemed to help institutions take precautions related to the possible problems that can be faced in distance education applications

An Implementational Concept of the Autonomous Machine Tool for Small-Batch Production

The increasing demand for customized and complex products with small batch sizes confronts the manufacturing industry with new challenges, which can only be handled by flexible and dynamic manufacturing processes. As a major part of the process chain, autonomous machine tools can contribute to satisfying these requirements. Although there are many contributions on autonomous machine tools in research, the development of a self-learning, autonomous AI-integrated machine tool has been implemented neither in the industry nor in research. This paper proposes an industry-oriented concept of a self-learning machine tool. The system architecture consists of the existing CAD, CAM and CNC process chain and extends it with a knowledge base and an intelligent CAPP system for domain knowledge representation and decision making. Process knowledge is represented by using a continual learning process simulation approach for small-batch production

Eight-year follow-up of uncemented hydroxyapatite coated hip prosthesis for hip osteoarthritis secondary to developmental hip dysplasia [Gelişimsel kalça displazisi zemininde gelişen osteoartritli kalçalarda kullanilan çimentosuz hidroksiapatit kapli kalça protezlerinde sekiz yillik izlem]

Objectives: This study aims to investigate the mid-term clinical and radiological results of cementless hydroxyapatite coated total hip arthroplasty (THA) for hip osteoarthritis due to developmental dysplasia of the hip (DDH). Patients and methods: Between January 2004 and December 2010, 34 hips (12 Crowe type I, 12 Crowe type II, 4 Crowe type III, 6 Crowe type IV) of 30 patients (22 females, 8 males; mean age 53.4 years; range 30 to 75 years) with degenerative arthritis due to DDH were analyzed in terms of cementless hydroxyapatite coated acetabular component (EPF Plus®) over Zweymüller femoral component (Zweymüller SL-PLUS®) and porous coating. Clinical assessment was performed using Harris hip scores (HHS) preoperatively and at the last clinic visit, while radiological assessment was done according to the Callaghan and Engh's criteria. Results: The mean follow-up was 48 months (range, 25-91 months). The mean HHS was 44.97 (28-55) preoperatively and 92.25 (69-100) at the last visit. All femoral components were graded as stable according to Callaghan and Engh's criteria. Radiolucency was mostly observed in Gruen zones 1 and zone 7 of the femur [zone 1; 20 hips zone 7; 19 hips zone 2; one hip, zone 3; one hip and zone 6 one hip]. Around acetabular component, radiolucency was detected in zone 2 in 12 hips, zone 3 in 10 hips and zone 1 in six hips. Heterotopic ossification developed in two hips, while neuropraxy was detected in two hips postoperatively. Femoral fissure in one hip, nonunion in the femoral osteotomy line in one hip, and femoral head autograft nonunion in one hip developed. Conclusion: Mid-term results of uncemented Zweymüller femoral stem and hydroxyapatite coated press-fit using acetabular components for THA femoral stem are excellent

A comparison of the measurements with biochemical markers of bone turnover and bone mineral density in the assessment of the efficiency of osteoporosis treatment [Osteporoz tedavisinin etkinliginin degerlendirilmesinde kemik döngüsü biyokimyasal belirteçleri ve kemik mineral yogunlugu ölçümlerinin karşilaştirilmasi]

Objectives: This study aims to compare the measurements using biochemical markers of bone turnover and bone mineral density (BMD) in the assessment of the efficiency of osteoporosis treatment. Patients and methods: Between March 2006 and December 2008, 166 patients with osteoporosis in our clinic were included. Patients who were out of contact due to death or other reasons during follow-up were excluded. We compared the measurements of urinary biochemical markers of bone turnover using cross-linked N-telopeptide (Ntx) values and BMD in 60 patients (49 females, 11 males; mean age: 65.7 years; range: 42 to 87 years) with osteoporosis who were treatment-naive and completed study. Results: Twenty-nine (48.3%) of the patients received surgical treatment, while 31 (51.7%) received conservative therapy. Urine NTx values of the patients decreased 38.82% at three months; 51.99% at six months and 66.41% at 12 months. Lumbar vertebra BMD increased by 20.7% and femur neck BMD increased by 11.9% at the end of the first year. Conclusion: Urine NTx values respond to osteoporosis treatment faster than BMD measurements; thereby it may be suitable to use this parameter for the monitorization of the treatment efficiency