Optimization of 5-axis milling processes using process models

Productivity and part quality are extremely important for all machining operations, but particularly for 5-axis milling where the machine tool cost is relatively higher, and most parts have complex geometries and high quality requirements with tight tolerances. 5- axis milling, presents additional challenges in modeling due to more complex tool and workpiece interface geometry, and process mechanics. In this paper, modeling and optimization of 5-axis processes with cutting strategy selection are presented. The developed process models are used for cutting force predictions using a part-tool interface identification method which is also presented. Based on the model predictions and simulations, best cutting conditions are identified. Also, for finish process of a complex surface, machining time is estimated using three machining strategy alternatives. Results are demonstrated by example applications, and verified by experiments

Investigation of lead and tilt angle effects in 5-axis ball-end milling processes

5-axis milling is widely used in aerospace, die-mold and automotive industries, where complex surfaces and geometries are machined. Being special parameters of 5-axis milling, lead and tilt angles have significant effects on the process mechanics and dynamics which have been studied very little up to now. In this paper, first of all, effects of tool tip contact on the surface finish quality is presented, and conditions to avoid tip contact in terms of lead and tilt angles and depth of cut are stated. The effects of lead and tilt angles on cutting forces, torque, form errors and stability are investigated through, modelling and verified by experimental results. It is shown that the cutting geometry, mechanics and dynamics vary drastically and nonlinearly with these angles. For the same material removal rate, forces and stability limits can be quite different for various combinations of lead and tilt angles. The results presented in the paper are expected to help understanding of complex 5-axis milling process mechanics and dynamics in a better way. The results should also help selection of 5-axis milling conditions for higher productivity and machined part quality

Machining strategy development in 5-axis milling operations using process models

Increased productivity and part quality can be achieved by selecting machining strategies and conditions properly. At one extreme very high speed and feed rate with small depth of cut can be used for high productivity whereas deep cuts accompanied with slow speeds and feeds may also provide increased material removal rates in some cases. In this study, it is shown that process models are useful tools to simulate and compare alternative strategies for machining of a part. 5-axis milling of turbine engine compressors made out of titanium alloys is used as the case study where strategies such as flank milling (deep cuts), point milling (light cuts) and stripe milling (medium depths) are compared in terms of process time by considering chatter stability, surface finish and tool deflections

The importance of extrinsic cues in deciding to purchase meat products: A conjoint analysis on Muslim consumers

Purpose: This study aims to investigate how extrinsic cues such as brand, certification, production method and price affect Muslim soujouk consumers’ purchasing decisions in Turkey. Design/methodology/approach: Conjoint analysis was used to identify consumers’ preferences and cluster analysis was used to reveal consumer segments for Turkish soujouk, which is a kind of fermented sausage. A total of 270 Muslim consumers from Turkey were selected by using a convenience sampling method. Four extrinsic cues were selected for analysis: brand (unbranded product, private label and national brand), certification (Turkish Standards Institution, geographical indication and halal certificate), production method (heat process and fermentation) and price (TRY11, TRY15 and TRY19). Findings/results: Brand, certification, production method and price were found to be significant for consumer preference. Price was the least important attribute in consumer purchase intention. National brand and halal certification were amongst the most important levels. The research also revealed two basic consumer segments according to cluster analysis. Practical implications: The study has practical significance for manufacturers in Muslim countries to identify the main extrinsic cue that influences consumers’ preferences in meat products. This result provides important insights to both local producers and foreign manufacturers that market their meat products to Muslim society. Originality/value: This is the first study on Turkish Muslim consumers’ preferences towards meat products analysing extrinsic product attributes. In addition, conjoint analysis and cluster analysis are used to specify Muslim consumers’ preferences

Analysis Of Intramuscular Injectıons Admınıstered In A Family Health Center

Objectives: In this study, the objective was to evaluate the intramuscular injections administered to patients admitted to a family health center with sociodemographic characteristics. Materials and Methods: This is a cross-sectional, analytical and, retrospective file review study. The sample population was formed by patients who had intramuscular injections administered between the dates of January 01, 2017 - and December 31, 2019. A total of 5648 injections for 2059 adults/children were evaluated. The data set was analyzed using SPSS 17.0 (IBM, USA) statistical package program. Results: An average of 2.74 injections per person was administered. The rate of myorelaxant injection administration was higher among women (p<0.001), and the rate of antibiotic and analgesic + myorelaxant injection administrations was higher among men (p<0.001 for both). With the increase of age, the rate of analgesic injection administrations increases (p<0.001) and the rate of antibiotic injection administrations decreases (p<0.001). The highest analgesic + myorelaxant injection administration rate was during autumn, and the lowest was during winter (p=0.001). Conclusion: The results showed that the frequency of analgesic, myorelaxant, antibiotic, steroid, vitamin/mineral, hormone and combination drugs used for intramuscular injection were affected by demographic variables such as age, gender and season. Identifying family health center dynamics may contribute to creating rational health policies. © Ankara Medical Journal.All rights reserved

What factors affect voting behavior in elections? A research on generation Z

Bu çalışmanın amacı teknoloji çağının çocukları olarak ifade edilen Z kuşağı seçmeninin oy verme davranışını araştırmaktır. 2023 yılı genel seçimlerinde yaklaşık 7 milyon genç seçmen oy kullanacaktır. Bu genç seçmenin sosyolojik, sosyo-psikolojik ve rasyonel oy verme davranışları üzerinde hangi faktörlerin etkili olacağı araştırmanın konusunu oluşturmaktadır. Bu bağlamda, Z kuşağının aktif olarak kullandığı sosyal medya, etkisi altında kaldıkları referans gruplar ve sahip oldukları politik ilgilenimleri ile oy verme davranışları arasındaki ilişki araştırılmaktadır. Çalışmanın evrenini 2000 yılı ve civarı doğumlu Z kuşağı oluşturmaktadır. Veriler web tabanlı anket yöntemi ile 182 katılımcıdan elde edilmiştir. Katılımcılar kolayda örnekleme yöntemi ile belirlenmiştir. Araştırma modeli PLS (Kısmi En Küçük Kareler) tabanlı yapısal eşitlik modellemesi ile test edilmiştir. Verilerin sınıflandırılmasında ise SPSS v23 istatistik programı kullanılmıştır. Araştırmanın sonuçlarına bakıldığında hem sosyal medyanın hem de referans grup etkisi ve politik ilgilenimin üçünün de sosyo-psikolojik oy verme üzerinde etkili olduğu görülmektedir

Modeling and simulation of 5-axis milling processes

5-axis milling is widely used in machining of complex surfaces. Part quality and productivity are extremely important due to the high cost of machine tools and parts involved. Process models can be used for the selection of proper process parameters. Although extensive research has been conducted on milling process modeling, very few are on 5-axis milling. This paper presents models for 5-axis milling process geometry, cutting force and stability. The application of the models in selection of important parameters is also demonstrated. A practical method, developed for the extraction of cutting geometry, is used in simulation of a complete 5-axis cycle

The Retrospective Evaluation of the Patients in Pediatric Cardiac Intensive Care Unit of Cardiac Surgery Center

Introduction:In this study, demographic and epidemiologic features, clinic and prognosis of patients admitted to the pediatric cardiac intensive care (PCICU) unit of a cardiac surgery center were analysed retrospectively.Methods:Patients followed in the PCICU between January 2017 and January 2018 were included in the study. Patient files were analysed for medical data. The patients were divided into 4 major categories as postoperative patients (group 1), patients followed after cardiac catheterization (group 2), patients followed due to arrythmias (group 3), and others (myocarditis, pneumonia, tamponade) (group 4). The demographic variables, such as age and gender, echocardiographic diagnosis, kind and condition of the transfer, reason for PCICU follow-up, and discharge status were evaluated in detail.Results:Eighty hundred ninety five patients were followed in the PCICU during the study period.The median age was 5.5 months (1 day-18 years). 53% of patients (n=474) were male and 47% (n=421) were female. The ortanca weight of the patients was 7.2 kg (1.8-80 kg). 16% of the patients were younger than 1 month of age and 54% of the patients were under the age of 6 months. 12% (n=107) of the patients had a diagnosis of a genetic condition such as Down syndrome, DiGeorge syndrome, etc. 40% of the patients were non-residents. 25% was transferred by air ambulance or ground ambulance. 22% of the patients were foreigners. There were 610 patients in group 1, 130 patients in group 2, 55 patients in group 3, and 100 patients in group 4. The RACHS-1 scores in group 1 were as follows: 0.8% undetermined, 11.2% category 1, 42.9% category 2, 29.6% category 3, 12.6% category 4,(-) category 5, and 2.6% category 6. Overall mortality was 5.9% (n=53) and morbidity was 22% (n=197).Conclusion:We believe that by the means of this kind of epidemiological studies, we may detect the types of cardiac problems in children who needed intensive care follow-up and help to decrease mortality and morbidity in childhood due to congenital cardiac diseases in our country

İki Pozitif Azot Atomu İçeren Di-katyonik Yüzey Aktif Maddelerin Sentezi ve 1.0 M HCl Ortamında Korozyon İnhibisyon Etkinliklerinin İncelenmesi

Bu çalışmada, kimyasal yapısında iki adet pozitif yüklü kuaterner amonyum azotu içeren üç tane di-katyonik yüzey aktif madde sentezlenmiştir. Sentezlenen yüzey aktif maddelerin kimyasal yapıları çeşitli spektroskopik yöntemlerle (FT-IR, 1H NMR ve 13C NMR) ispatlanmıştır. Sentezlenen ve moleküler yapıları aydınlatılan 3 adet ürünün, 1.0 M HCl asidik ortamda, kütle kaybı yöntemi kullanılarak yumuşak çeliğin korozyonuna karşı inhibisyon etkinlikleri belirlenmiştir. Farklı inhibitör konsantrasyonlarına sahip asidik çözeltilere, metal kuponların, oda sıcaklığında 24 saat süreyle daldırılması suretiyle yapılan korozyon testleri sonucunda, her üç yüzey aktif madde için, birbirine yakın ve etkin inhibisyon verimleri elde edilmiştir. Moleküler yapılarında bulunan uzun karbon zincirindeki karbon sayısının fazlalığı korozyona karşı korumada etkin bir faktör olduğu gösterilmiştir. Uzun zincirindeki karbon sayısı en fazla olan inhibitörün asit ortamındaki korozyon inhibisyon etkinliğinin diğerlerine göre biraz daha yüksek olduğu tespit edilmiştir. Bunun yanı sıra, korozyona karşı etkinlikleri ile ilişkilendirmek adına, söz konusu di-katyonik yüzey aktif maddeler için kritik misel konsantrasyonu, bu konsantrasyondaki yüzey gerilimleri, misel oluşum serbest enerjisi, köpük kararlılığı gibi bazı fizikokimyasal parametreleri de hesaplama yoluna gidilmiştir. Yüzey aktif maddelerin metal yüzeyine adsorbe olarak yüzeyi korozyondan koruduklarının önemli bir destekleyici delili olan taramalı elektron mikroskobu (SEM) ile yüzey görüntüleri de alınmış ve asit çözeltisine daldırılan metal yüzeylerindeki pürüzlülük halleri belirlenmiştir

The frequency of Duchenne muscular dystrophy/Becker muscular dystrophy and Pompe disease in children with isolated transaminase elevation: results from the observational VICTORIA study

IntroductionElevated transaminases and/or creatine phosphokinase can indicate underlying muscle disease. Therefore, this study aims to determine the frequency of Duchenne muscular dystrophy/Becker muscular dystrophy (DMD/BMD) in male children and Pompe disease (PD) in male and female children with isolated hypertransaminasemia.MethodsThis multi-center, prospective study enrolled patients aged 3–216 months with serum alanine transaminase (ALT) and/or aspartate transaminase (AST) levels &gt;2× the upper limit of normal (ULN) for ≥3 months. Patients with a known history of liver or muscle disease or physical examination findings suggestive of liver disease were excluded. Patients were screened for creatinine phosphokinase (CPK) levels, and molecular genetic tests for DMD/BMD in male patients and enzyme analysis for PD in male and female patients with elevated CPK levels were performed. Genetic analyses confirmed PD. Demographic, clinical, and laboratory characteristics of the patients were analyzed.ResultsOverall, 589 patients [66.8% male, mean age of 63.4 months (standard deviation: 60.5)] were included. In total, 251 patients (188 male and 63 female) had CPK levels above the ULN. Of the patients assessed, 47% (85/182) of male patients were diagnosed with DMD/BMD and 1% (3/228) of male and female patients were diagnosed with PD. The median ALT, AST, and CPK levels were statistically significantly higher, and the questioned neurological symptoms and previously unnoticed examination findings were more common in DMD/BMD patients than those without DMD/BMD or PD (p &lt; 0.001).DiscussionQuestioning neurological symptoms, conducting a complete physical examination, and testing for CPK levels in patients with isolated hypertransaminasemia will prevent costly and time-consuming investigations for liver diseases and will lead to the diagnosis of occult neuromuscular diseases. Trial RegistrationClinicaltrials.gov NCT04120168