Tersanelerdeki İş Kazalarının İstatistikî Olarak İncelenmesi

Increase of shipyard accidents at Tuzla shipyards in Turkey has attracted public attention towards shipbuilding sector and the activities at shipyards have undergone a close scrutiny. In this paper, shipyard accidents both here in Turkey and in the world were studied statistically. Within the context of this study, accidents occurred in Hong Kong, Singapore, USA and the UK has been analyzed and evaluated in terms of their causes and effects in a wider perspective. Some conclusions have also been drawn based on the data availabl

ANOTHER BLOW ON THE TORN DOWN WALL-THE INCLINING EXPERIMENT

The classical method (namely inclining experiment) has been used to estimate the vertical center of gravity (VCG or more often KG) of ships for many years. This method is based on the assumption that the metacenter is unchanged in the calculation of KG when the vessel is heeled. However, ships built today have knuckles, chines, dead-rise which may give rise to excessive change in the water-plane. The location of the metacenter is changed on these vessels when heeled. Therefore, determination of the vertical center of gravity may be somewhat erroneous. In this study, three different methods based on the assumption of unchanged metacenter have been examined. Employing the Graphical method, Polar method and Generalized method, the KG values of all vessels can be calculated without any dependence on the metacenter. The three methods mentioned in this study were studied and applied on ten different ships. Furthermore, the results from the classical method compared with those obtained from the recently developed methods. Based on this comparison, it is observed that the new methods developed have similar results to the classical method. Therefore, these methods may be a good alternative to the inclining experiment in the future. Moreover, uncertainty analyses have been performed for the results obtained from the classical method just to realize if there are any critical GM values within the margin of error

Effect of loading conditions on ship stability during a voyage

Denizde seyreden gemilerin davranışları statik olarak veya rüzgar, dalga gibi parametreleri de sistemin içine alacak biçimde yarı-statik olarak incelenir. Sefer esnasında gemilerin statik ve dinamik hareketleri, yük durumundaki değişikliklere bağlı olarak farklılık gösterebilir. Bu değişikliklerin, uluslararası kuruluşların koyduğu kriterler çerçevesinde olması gerekir. Bu çalışmada, gemi stabilitesi, sefer sırasında meydana gelen yükleme değişiklikleri dikkate alınarak statik ve dinamik halde incelenmiştir. Statik analiz konvansiyonel metodlarla gerçekleştirilirken, dinamik analiz ise bilgisayar programı destekli, güvenilir ve lineer olmayan bir yalpa hareketi modeli yardımıyla yapılmıştır. Stabilite performansının gemi tiplerine göre değişimini görmek amacıyla dört farklı gemi seçilmiştir. Sonuçlar karşılaştırmalı olarak tablolar ve grafikler halinde sunulmuştur.Anahtar Kelimeler: Duffing denklemi, lineer olmayan hareketler, yalpa, gemi dinamiği.  In general, ship behaviors at sea are analyzed either statically or so-called quasi-statically which introduces a number of dynamic effects such as steady wind and wave forces into the system. Breaking down stability into two parts and considering each one as an independent case may lead one to evaluate ship behaviors erroneously. Stability and dynamic behaviors of a ship undergo variations while her loading condition changes constantly during one leg of her trip. Thus, these variations have to be within the acceptable margins which international societies stipulate. In this study, ship stability is assessed both statically and dynamically over a range of loading conditions that a ship experiences throughout her voyage. Statical analysis has been carried out by conventional methods whereas dynamical assessment has been implemented by a proven nonlinear roll motion model supported with a suitable computer code. Four ship types are chosen to investigate overall stability performance for different loading conditions in order to analyze changes from one type to the other.Keywords:  Duffing?s equation, nonlinear motions, rolling, ship dynamics

The effect of the pre-outfit and pre-pipe assemblies on shipyard efficiency

Çoğu endüstriyel alanda olduğu gibi, gemi inşa sektöründe de süreç iyileştirme çalışmaları son derece önemlidir. Günümüzde, tersanelerin rekabet avantajını sağlayabilmeleri ve varlıklarını devam ettirebilmeleri için üretim süreçlerini gözden geçirerek, çıktıyı artırabilecek iyileştirmeleri sağlamaları ve bunun sonucunda daha kısa sürede ürün teslimini gerçekleştirmeleri gerekmektedir. Ürün çevrim süresinin veya diğer bir ifadeyle imalat temin süresinin kısaltılması, tersanelerin yıllık üretim kapasitelerinin ve buna bağlı olarak pazar payının artmasına neden olacaktır. Bunların gerçekleştirilebilmesi için, tersanelerin, mevcut üretim sistemlerini detaylı bir biçimde analiz etmeleri ve sistem üzerinde çeşitli iyileştirmeleri yapması gerekmektedir. Bu çalışmada, bir iyileştirme süreci modeli belirlenmiş ve ele alınan bir çift dip bloğunun teçhiz ve boru montaj işlemlerinin tamamının blok montaj istasyonunda değil kısmen daha önceki istasyonlarda yapılması durumunda sistemin çıktı miktarının nasıl değiştiği izlenmiştir. Öncelikle, bir iyileştirme süreci modeli ortaya konulmuştur. İyileştirme süreci modeli, sürekli iyileştirme (Kaizen), darboğaz teorisi (OPT) ve Arena simülasyon gibi süreçleri içermektedir. Model içerisindeki adımlar, sırasıyla takip edilmiş ve mevcut üretim sisteminde, tamamı blok montaj sahasında yapılan teçhiz ve boru montaj işlemlerinin ön istasyonlarda yapılmasının sistemin çıktısına olan etkisi incelenmiştir. Çalışmanın sonunda, teçhiz ve boru montaj işlemlerinin daha önceki istasyonlarda yapılmasıyla ve mevcut durum üzerinde bazı ufak değişikliklerin yapılmasıyla birlikte sistemin belirli bir sürede ürettiği blok sayısının yani çıktı miktarının arttığı görülmüştür. Dolayısıyla, ön teçhiz ve ön boru montaj işlemlerinin tersane üretim sisteminin performansını artırdığı teorik olarak gösterilmiştir.  Anahtar Kelimeler: Sürekli iyileştirme, darboğaz ilkesi, Arena simülasyon, ön teçhizleme, ön boru montaj.In recent years, the competition is very hard in shipbuilding industry just like other industries. In this competitive environment, it is very important that the companies work efficiently. In shipbuilding industry, the production should be performed in effective way so that the shipyards keep their competitive power against their competitors. The most important and serious competitors are the far eastern shipyards.  The shipyards located in the far eastern countries have a serious competitive power. A ship can be launched in shorter time by the far eastern shipyards and also the costs are lower. By doing that, they meet the customer demands and sell a lot of ships and extend their market share. To keep competitive power, a shipyard needs to produce more ships in a given time or, in other words, reduce cycle time. To be able to produce a ship in shorter time and increase the system throughput, the first step is to analyze the current production system in detail and identify the processes. After the whole processes are identified, the activities which take long time and the unnecessary activities should be found. For doing this, all the activities should be investigated. The activities taking long time should be shortened and the unnecessary activities should be removed. As the processes and activities in the shipyard production system are investigated, it can be seen that a lot of shipyards perform their outfit and pipe works in block assembly area after the completion of the steel works. In other words, firstly, the steel works is completed, secondly, the outfit works and finally the pipe works are performed. All this works are carried out one after the other. So it takes a long time and the cycle time of a block is quite long. The longer the cycle times of blocks are, the longer the whole ship cycle time is. If the cycle time of a ship is long, then number of ships produced annually is lower. This, also, reduce the shipyard annual income. A double bottom block, a part of a container ship of 1150 TEU, was presented here as a sample case study. The block considered here covers almost all the work stations joining its production. Consequently, all the steel work activities in double bottom block production were taken into the process and the field of the study was extended. In this study, it is aimed to determine the effect of pre-outfit and pre-pipe assemblies on the system throughput. So, the whole of the outfit and pipe works weren?t performed in block assembly area, instead, some assembly works of outfits and pipes were performed in previous work stations. In this way, the effects of the pre-outfit and pre-pipe assemblies were seen. During this study, an improvement process model was proposed and applied. This model includes the continuous improvement process (Kaizen), bottleneck theory (OPT: Optimized Production Techniques) and Arena simulation. The steps in this model were followed one by one. In the model, the current case analysis was examined in detail and the parallel and serial work activities were determined. Considering these parallel and serial activities, the completion times of all work stations were found. Then, the current case was modeled in Arena simulation program and the data such as number of blocks produced in a given period and the waiting time were calculated. By using this data, it was seen that how many blocks the current system could produce and what work station in bottleneck situation.  As a result of the simulation study, the block assembly station was found as a bottleneck of the process. In the other step, considering the bottleneck theory, some improvement suggestions were identified on the bottleneck station. The suggestions were mainly based on pre-outfit and pre-pipe assemblies. Then the suggestions were applied on the current case and the new case was achieved. By modeling the new case in Arena simulation program, some data were taken from simulation and compared with the new case. In this comparison, in a same working period, it was seen that the new case could produce more blocks than that of the current case. In other words, in the new case, the cycle time of a block is shorter than the current one. As a result, by performing outfit and pipe assemblies in earlier work stations, a shipyard can increase its throughput considerably.  Approximate increase of 33% in block quantity in a given period was achieved. This is an important improvement rate and it gives a great competitive advantage to a shipyard. Keywords: Continuous improvement (Kaizen), bottleneck theory, Arena simulation, pre-outfit assembly, pre-pipe assembly

Türkiye’de diş hekimlerinin bifosfonatlar konusundaki farkındalık ve bilgilerinin değerlendirilmesi

Aim: Bisphosphonates (BPs) are inorganic pyrophosphate analogs used for the treatment of various diseases. This study aimed to evaluate the knowledge and attitudes of general dental practitioners (GDP), specialist trainees (ST), and specialists (S) in Turkey toward medication-related osteonecrosis of the jaw (MRONJ) and to optimize future training programs in this field. Materials and Methods: A self-report questionnaire consisting of 7 questions about demographic data, knowledge about BPs, MRONJ and treatment modalities was prepared and send to the members of Turkish Dental Association via email. Results: A total of 209 participants were included in this survey. The mean age of the ST group was significantly lower than the mean ages of the GDP and S groups (P= 0.003, P= 0.038). GDP are less likely to think of BPs administration and radiotherapy treatment than S or ST upon observation of an exposed bone in the head-and-neck region (P=0.048, P=0.008). In comparison to the S and ST groups, the GDP group displayed less knowledge regarding the radiological and intraoral examination of patients undergoing BP therapy (P= 0.034). Conclusion: The increasing awareness of dentists about usage and side effects of BPs is important for preventing MRONJ. The GDP group displayed significantly less knowledge regarding the radiological and intraoral examinations of patients undergoing BP therapy. Greater efforts are required to increase education and knowledge of MRONJ and BPs among dental practitioners.Amaç: Bisfosfonatlar çeşitli hastalıkların tedavisinde kullanılan inorganik pirofosfat analoglarıdır. Bu çalışma uzman olmayan diş hekimlerinin, uzmanlık öğrencilerinin ve uzmanların ilaca bağlı gelişen çene osteonekrozuna yönelik bilgi ve tutumlarını değerlendirmenin yanında, gelecekteki eğitim programlarını optimize etmeyi amaçlamıştır. Materyal ve Metot: Çalışmaya 209 katılımcı dahil edilmiştir. Türk Dişhekimleri Birliği’nin desteğiyle bir anket hazırlanmış ve üyeler arasında e-posta ile paylaşılmıştır. Katılımcıların demografik bilgiler, ilaca bağlı çene osteonekrozları, bisfosfonatlar ve tedavi yaklaşımları ile ilgili 7 sorudan oluşan anketi yanıtlamaları istenmiştir. Bu anket sorularına hekimlerin verdiği cevaplar sayı ve yüzde ile tanımlanmıştır. Bulgular: Ankete katılan uzmanlık öğrencilerinin ortalama yaşı, uzman olmayan diş hekimleri ve uzmanlardan anlamlı olarak düşük bulunmuştur (P = 0.003, P = 0.038). Uzman olmayan diş hekimleri, baş-boyun bölgesinde gözlemlenen ekspoze kemiğin bisfosfonat tedavisi ya da radyoterapiye bağlı olabilme ihtimalini diğer gruplara göre daha az değerlendirmiştir (P=0.048, P=0.008). Uzman ve uzmanlık öğrencilerine kıyasla uzman olmayan diş hekimleri, bisfosfonat kullanan hastaların radyolojik ve ağız içi bulguları hakkında daha az bilgi sahibi olduğunu belirtmiştir (P = 0.034). Sonuç: Diş hekimlerinin bisfosfonatların kullanımı ve yan etkileri konusunda artan farkındalığı MRONJ’un önlenmesi için önemlidir. Diş hekimleri arasında MRONJ ve bisfosfonatlar ile ilgili bilincin artırılması için daha fazla çaba gösterilmesi ve hedef kitleye yönelik eğitim planları oluşturulması gerekmektedi

Sub- and super-shear ruptures during the 2023 Mw 7.8 and Mw 7.6 earthquake doublet in SE Türkiye

An earthquake doublet (Mw 7.8 and Mw 7.6) occurred on the East Anatolian Fault Zone (EAFZ) on February 6th, 2023. The events produced significant ground motions and caused major impacts to life and infrastructure throughout SE Türkiye and NW Syria. Here we show the results of earthquake relocations of the first 11 days of aftershocks and rupture models for both events inferred from the kinematic inversion of HR-GNSS and strong motion data considering a multi-fault, 3D geometry. We find that the first event nucleated on a previously unmapped fault before transitioning to the East Anatolian Fault (EAF) rupturing for ~350 km and that the second event ruptured the Sürgü fault for ~160 km. Maximum rupture speeds were estimated to be 3.2 km/s for the Mw 7.8 event. For the Mw 7.6 earthquake, we find super-shear rupture at 4.8 km/s westward but sub-shear eastward rupture at 2.8 km/s. Peak slip for both events were as large as ~8m and ~6m, respectively

Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good