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  • Öğe
    Kalın kesitli hadfield çeliklerine karbon ve molibden ilavesinin etkisinin incelenmesi
    (Osman Sağdıç, 2023) Öztürk, Faruk; Gürol, Uğur; Uysal, Mehmet
    Hadfield çelikleri madencilik endüstrisinde özellikle yüksek tokluk ve aşınma direnci gerektiren astar plakalarında, konik kırıcıların cevher ile temas eden ve cevheri öğüten kırıcı mantolarında, kırıcı çenelerinde ve iş makinalarının yürüyüş takımlarında yaygın bir şekilde kullanılmaktadır. Bu çeliklerde artan kalite gereksinimleri nedeniyle, daha yüksek tokluk ve aşınma özellikleri elde etmek için dökümhanelerin Ar-Ge departmanları tarafından alaşım geliştirme ve ısıl işlem optimizasyon çalışmaları önem kazanmaktadır. Bu çalışmada kalın kesitli Hadfield çeliklerinde karbon ve molibden ilavesinin mikro yapı ve mekanik özelliklere etkisi incelenmiştir. Döküm numunelerinin karakterizasyonu için mikro yapı incelemelerine ek olarak sertlik, çekme ve darbe çentik testleri uygulanmıştır. Elde edilen sonuçlar en yüksek çekme ve süneklik değerlerinin düşük karbon içeriğine sahip (1.09%C) molibdensiz analiz ile elde edilebileceğini göstermiştir. Ayrıca, daha yüksek akma mukavemetine sahip karbürsüz bir yapı eldesi için molibden ilavesi olması durumunda ise ısıl işlem sıcaklığının veya süresinin arttırılması gerektiğini ortaya koymuştur.
  • Öğe
    Thermal management analysis with different PCMs in Sodium-Ion batteries
    (Türkiye Enerji Stratejileri ve Politikaları Araştırma Merkezi (TESPAM), 2024) Canci Matur, Utku; Tüysüz, Cansu; Köse, Ali
    The advent of modern technology has led to a significant increase in the utilisation of rechargeable secondary batteries. Despite the sustainability of lithium-ion (Li-ion) batteries, the limited availability of lithium has driven research into alternative energy storage technologies. Sodium-ion (Na-ion) batteries, as a potential alternative to Li-ion batteries, have emerged as a highly promising contender. However, for these batteries to become industrially viable, certain properties such as energy and power density need to be enhanced. To address this issue, batteries have been a focus of research, and battery thermal management systems have been developed. These systems aim to evaluate battery performance, which is strongly influenced by temperature. Effective thermal management ensures that the battery operates within the optimal temperature range. This study models a pouch-type battery and evaluates the effects of phase changing materials (PCM) on battery temperature control. Comparative analysis is conducted using different PCMs to understand their impact. The study analyses the battery's response to specific temperature ranges and assesses how different PCMs affect battery cooling performance. The results provide critical insights for ensuring efficient battery operation. Furthermore, this research supports the broader adoption of Na-ion batteries in industrial applications and contributes to the development of sustainable energy storage systems.
  • Öğe
    S355J2 yapı çeliklerinin toz altı ark kaynağında dolgu metalinin mikroyapı ve mekanik özelliklere etkisi
    (İdris Karagöz, 2024) Varol, Abdullah; Bozan, Mehmet Safa; Çoban, Ozan; Gürol, Uğur
    Bu çalışmada 20 mm kalınlığa sahip S355J2 yapı çeliğine EN ISO 14171-A standardına göre üretilmiş GeKa S1, S2Si ve S3Mo dolgu metalleri kullanılarak toz altı ark kaynağı yöntemi ile alın kaynağı prosesi gerçekleştirilmiştir. X kaynak ağzı geometrisi ve 600 kaynak ağzı açısı ile EN ISO 147174 standardına uygun olarak üretilmiş alüminat bazik Eliflux BFPP (SAAB66ACH5) tozu kullanılarak kaynak işlemleri uygulanmıştır. Kaynak prosesi sonrasında tahribatsız muayene, makro yapı incelemesi, mikroyapı incelemesi ile mikrosertlik, eğme, çekme ve -20 0C’de kaynak metali ve ısıdan etkilenmiş bölge (IEB)’den çentik darbe testleri gerçekleştirilerek kaynaklı yapılar karakterize edilmiştir. Farklı dolgu metalleri kullanılarak elde edilen kaynaklı yapıların özellikleri kıyaslanarak kullanım alanında beklenen performansa yönelik olarak dolgu metali seçimi için mikroyapı – mekanik özellik ilişkisi kurulmuştur. Elde edilen sonuçlar S1 dolgu metali ile yapılan kaynakların kaynak bölgesinden; S2Si ve S3Mo dolgu metalinde ana malzemeden koptuğunu göstermiştir. Her üç kaynakta da akma ve çekme dayanımı ve %uzama değerlerinde bariz bir farklılık gözlenmemiştir. Fakat S1’e kıyasla S3Mo kullanımı nedeniyle kaynak metali ve IEB’deki çentik darbe dayanımında sırasıyla %15 ve %166, mikrosertlikte %37 ve %8’lik artış sağlanmıştır. Sonuç olarak denizcilik endüstrisinde kullanılan yapı çeliklerinin kaynak uygulamalarında S2Si ve S3Mo dolgu metallerinin kullanımının mikroyapı ve mekanik özellikler açısından uygun olduğu fakat maliyet/performans açısından değerlendirildiğinde ise S2Si teli kullanımının, düşük sıcaklıklarda yüksek darbe dayanımı gereksiniminin arttığı kritik uygulamalarda ise S3Mo dolgu metali kullanımının daha uygun olacağı ortaya koyulmuştur.
  • Öğe
    Superconductivity in brain
    (Bingol University, 2024) Aslan Çataltepe, Özden
    In this article, the phenomenon of superconductivity in the brain has been examined based on some properties of superconductivity. The possibility of hydrogen-based compounds to be superconducting at ambient temperature and pressure has enabled an analogy to be established between superconductivity and living organisms including high ratio water in other words hydrogen. In this context, the superconductivity phenomenon occurring in microtubules structures in neurons in the brain has been studied and thus the quantum mechanical properties of the brain have been tried to be explained. Due to the behavior of acting like computer memory, the role of repairing deoxyribonucleic acid damage, property of giving the quantum mechanical behavior to the brain, microtubules are very interesting organelles. Hence superconductivity with its extraordinary properties such as the quantum entanglement and bosonic state etc. may be guide for human beings in the respect of long term memory, empathy and consciousness.
  • Öğe
    Occupational health and safety practices in small and medium-sized enterprises in the construction sector and a new model proposal
    (Bursa Technical University, 2024) Altuntaş, Fatih; Ghasemlounia, Redvan
    The aim of the conducted study is to create a model that examines the average occupational safety performance level by considering both occupational health and safety performance in the workplace and occupational health and safety management system performance to improve the level of occupational health and safety in small and medium-sized construction companies. For this purpose, 34 small and medium-sized construction companies located in various cities in the Marmara Region constitute the sample group of the study. The data obtained from the sample group were analyzed using factor analysis and descriptive analysis in the SPSS program, and fuzzy logic method in the MATLAB program. With the fuzzy logic approach, two input variables and one output variable were created and defined with five parameters each. Subsequently, with 25 rules created using the fuzzy approach, the calculated average safety index was obtained as 5.69. It is observed that 18 construction companies, constituting 52.8% of the examined 34 small and medium-sized construction companies, have a low safety performance, while 16 construction companies, constituting 47.2%, exhibit high performance.
  • Öğe
    Investigation of an exact solution of a mixed boundary value problem using the residue method
    (Istanbul Gedik University, 2024) Sinsoysal, Bahaddin; Rasulov, Mahir A.
    In this study, a finite differences method is proposed for solving a mixed problem, which represents phenomena in hydrodynamics. To evaluate the approximate solution of the problem, its analytical solution is also constructed by the residue method developed by M.L. Rasulov, which is applied to find the solution of the partial differential equations containing time-dependent derivatives at boundary conditions. The formula for expansion of an arbitrary function in a series of residues of the solution of the corresponding spectral problem is used to show that the solution of the mixed boundary-value problem can be represented by the given residue formula. The use of the residual method gives an exact solution for the mixed boundary value problem, represented as a rapidly decreasing series. The derived formula makes it possible to formally establish both the existence and the uniqueness of the solution. Moreover, the derived formula provides a framework for evaluation, allowing a comparative analysis between the exact solution and the numerical approach.
  • Öğe
    In-plant logistics issues and methodologies analysis: case study
    (Istanbul Gedik University, 2024) Ateş, Ozan
    Inplant logistics, unlike other dimensions of logistics, has not been adequately analyzed in the literature and practices. Internal logistics, which can be defined as material transportation movements that occur in a closed area by nature, has a high impact on cost, quality and customer satisfaction in the relevant field. Lean logistics is the logistics dimension of lean production. Since logistics activities, like production activities, are ongoing activities, the improvements to be made will have a great impact. In this study, the solutions offered by a logistics company with problems related to internal logistics and the solutions offered by the author from a lean logistics perspective are included comparatively at the end of the study.
  • Öğe
    Mechatronics system design and implementation of a pneumatic hand rehabilitation device
    (Istanbul Gedik University, 2024) Gülnergiz, Emre Tuğberk
    This study presents the development of a mechatronic device for an additively manufactured Pneumatic Artificial Muscle (PAM) rehabilitation orthosis. Within this scope, the system's electro-pneumatic, mechanical, control, and software designs have been designed and implemented. The device, intended to directly interact with both patients and therapists within the bio-mechatronic process, is equipped with an intuitive graphical user interface (GUI). Utilizing a FlexSensor to measure hand flexion/extension angles, the device employs a solenoid valve, along with a trigger relay, for the inflation and deflation of the orthosis. During the electronic design phase, challenges such as interference and latency were mitigated through the implementation of isolations in the design. Employing a PD (Proportion-Derivative) control loop on the ATmega328 microcontroller, control parameters were determined empirically. By excluding a compressor pump inside the device, a lightweight, portable, and cost-effective system was accomplished. While potential enhancements discussed in the conclusion will be considered in future studies, the current prototype effectively fulfills the project objectives.
  • Öğe
    Dynamic simulation of the performance of a solar assisted heat pump in different climates
    (Istanbul Gedik University, 2024) Alipour, Bahareh; Karami, Maryam; Heidarnejad, Parisa
    One method to reduce energy consumption in buildings is using solar assisted heat pumps, in which the combination of heat pump and solar collector is used to improve the thermal performance. In this paper, TRNSYS and EES software are used to simulate the performance of an indirect expansion solar assisted heat pump. Dynamic simulation of the system is performed by changing parameters such as mass flow rate of collector working fluid and the collector area in five climates including Hot/Dry, Cold/Dry, Moderate/Humid, Hot/semi-Humid, and Hot/Humid. The results show that, in January, the Cold/Dry climate had the lowest free energy ratio (FER) because of high space heating load. In this month, Hot/semi-Humid climate has the highest FER, because of the higher solar radiation and no need to space heating. The annual FER in Hot/Dry zone is 71% which is higher than that other zones. The lowest FER related to Moderate/Humid climate due to high humidity and cloudiness.
  • Öğe
    Biological insights into energy storage technologies
    (Istanbul Gedik University, 2024) Kırmızıtaş, Fatma Ceren; Günder, Burhan Baran; Köse, Ali
    In the face of increasing energy demands and environmental concerns, the search for sustainable and efficient energy storage technologies has intensified. This review presents a holistic survey of innovative solutions by examining biological approaches. The study proceeds through three thematic sections: Biological Fuel Cells and Battery Systems, Photosynthesis and Solar Energy Storage, and Energy Generation at the Cellular Level. The first section, Biological Fuel Cells and Battery Systems describes the integration of biological processes into energy storage mechanisms. The use of biological systems and their contribution to the development of environmentally friendly and high performance energy storage technologies are discussed. In the 2nd section, Photosynthesis and Solar Energy Storage are very prominent in sustainability and energy efficiency issues in terms of both energy production and energy source food production while reducing carbon dioxide with photosynthesis-based energy storage methods. Energy production at the cellular level is discussed in the last section, Adenosine triphosphate (ATP), which is necessary for the cell to perform processes such as growth, reproduction and response to environmental stimuli, is characterized as the primary fuel. ATP production is carried out by mitochondria in animal cells and chloroplast in plant cells. Energy storage at the cellular level is carried out by molecules such as glycogen and lipids in animal cells and starch in plant cells. Considering all three issues, it has been observed that biological-based energy storage methods have numerous advantages in terms of sustainability and energy efficiency. In application areas where engineering approaches are at the forefront, it is thought that it may be possible to design more sustainable and highly energy efficient energy production systems by gaining new perspectives with biology-based simulation studies.
  • Öğe
    Developing soil liquefaction analysis program created on visual basic analysis in MS excel based on the 2018 Turkish seismic code
    (Istanbul Gedik University, 2024) Özcan, Mahmut; Nazilli, Hasan Bozkurt; Tolon, Mert
    The rapid increase in the world's population, the desire to revise old structures or to need new structures, and the decrease in usable areas in some big cities lead engineers to examine ground conditions more. Due to Turkey's location and geological structure, earthquake occurrences are quite high. The loss of life and property, which has increased with the earthquakes that have occurred in our country in recent years, has been examined and it has been seen that this situation is related to the ground factor rather than the superstructure design inadequacies. In this sense, the main goal of investors is to optimize the profit to be obtained by providing the aesthetics of the superstructure, comfort, and interior quality in building projects such as residences and offices. For this reason, geotechnical design is becoming a discipline that needs to be solved most economically. Starting the investment without paying due attention to the seismicity of the ground in the investment budgets, when the risk of liquefaction in the ground may come to the fore, it is possible to avoid unaccounted ground improvement methods, so new buildings with the risk of soil liquefaction are added to the unsafe old building stock. With the 2018 Seismic Code in Turkey, liquefaction on the ground and different problems that occur in the ground have been examined in more detail. Within the scope of the study, it was focused on getting faster results with faster and on-site determinations of the liquefaction situation on the ground, thanks to the Visual Basic application program prepared in Excel. In this sense, with the program prepared as the aim of the study, it is aimed to enable the construction of the soil liquefaction analysis to be made quickly and with less cost and to start the construction with a realistic budget and structural models. The program continuously increases its sensitivity and accuracy with additional inputs. This allows geotechnical engineers to achieve faster and earlier results Earthquake; Soil Liquefaction; TBDY; 2018 Turkish Seismic Code Regulation
  • Öğe
    Dielectric and optical properties of Eux(Bi1-x)Sr2CaCu2O6.5 (x=0.3 and 1) samples
    (Istanbul Gedik University, 2024) Canci Matur, Utku; Aslan Çataltepe, Özden; Tabanlı, Sevcan
    Eu-based copper oxide layered ceramics have some interesting dielectric properties depending on its stoichiometric ratios and elements used in ceramics. In this study, optical properties of EuSr2CaCu2O6.5 and Eu0.3Bi0.7Sr2CaCu2O6.5 samples and dielectric property of EuSr2CaCu2O6.5 sample were investigated for the first time. Negative real permittivity for EuSr2CaCu2O6+x sample was observed at temperature with 373 K and higher temperatures and below than the cross over frequency with 14 Hz. Moreover, it is determined that Eu3+ concentration in the material affects the relative emission intensity.
  • Öğe
    Using artificial ıntelligence algorithms to detect hate speech in social media posts
    (Istanbul Gedik University, 2024) Yerden, Aytaç Uğur; Turgut, Kadir
    Detecting hate speech on social media is of great importance to prevent negative impacts on people and communities and to remove such content. However, detecting hate speech is a complex and challenging process due to linguistic and cultural diversity. Therefore, it is important to develop powerful and effective machine learning algorithms. Since detecting such content using traditional methods can be time-consuming and costly, it is stated that artificial intelligence-based machine learning algorithms have great potential in this regard. The aim of this study is to evaluate the performance of artificial intelligence-based machine learning algorithms used in detecting posts containing hate speech on social media. The study focuses on the problem of detecting and managing hate speech on social media platforms. In this study, we will compare the performances of different algorithms and determine the most suitable methods. Additionally, the effects of the dataset and feature extraction methods on algorithm performance will be analyzed. Algorithms are often based on natural language processing techniques and try to detect hate speech by learning features in texts. The performance of these algorithms can vary depending on factors such as language, culture, the attributes they use, and the training dataset, so a comprehensive analysis is required. In the research, the performance of the algorithms used in detecting hate speech was compared with the dataset and feature extraction methods. In this process, the algorithms' linguistic and cross-cultural effectiveness, feature selection and representation, false positive and false negative rates, and overall accuracy will be analyzed.
  • Öğe
    Free volume impact on ionic conductivity of PVdF/GO/PVP solid polymer electrolytes via positron annihilation approach
    (Elsevier Ltd, 2025) Yılmazoğlu, Mesut; Okkay, Hikmet; Abacı, Ufuk; Tekay, Emre; Çoban, Ozan; Veziroğlu, Sümeyye; Yumak Yahşi, Ayşe; Tav, Cumali; Yahşi, Uğur
    This study reports the effects of free volume (FV) profiles on the ionic conductivities of PVdF/GO/PVP ternary polymer electrolytes using positron annihilation lifetime spectroscopy (PALS). The electrolytes were characterized by various tests such as FTIR, XRD, TGA-DTG, SEM, contact angle and DMA. FV profiles were evaluated by o-Ps lifetime (τ₃), intensity (I3) and FV fractions (fυ). PVdF exhibits a proton conductivity of 2.1 × 10⁻5 S/m at 80 °C. However, the introduction of GO leads to a decrease in conductivity, with PVdF/GO showing 1.7 × 10⁻5 S/m at 80 °C. The presence of PVP in PVdF/GO/PVP10 and PVdF/GO/PVP30 creates new FV spaces via hydrogen bonds and intermolecular interactions, expanding hydrophobic areas and increasing I₃ values. PVP's high mobility and positive charge density reduce the τ₃ values. In contrast, I₃ and fυ values decrease in PVdF/GO/PVP50, accompanied by a significant drop in τ₃ values and the proton conductivity and dielectric constant peak at 6.1 × 10⁻2 S/m and 77.38, respectively. High PVP concentration may enhance interactions within the polymer matrix, forming a dense structure that, despite reduced FV, maintains or enhances proton mobility through alternative conduction pathways and increased polarization. This study emphasizes the balance of FV and dielectric behavior for efficient electrochemical processes.
  • Öğe
    Geodesic path planning characteristics of the reconfigurable 1-S robot workspaces for hyperbolic, elliptical, and Euclidean geometries
    (Polska Akademia Nauk, 2024) Şahin, Haydar
    The path-planning strategies are implemented by establishing the Riemann curvature tensor and geodesic equations of the 1-S robot workspace. This paper’s originality lies in formulation of the parametric 1-S robot workspace for path planning, which is based on the differential geometry of the geodesic and Riemann curvature equations. The novel results in defining the path plan with diffeomorphic and expandable trajectories with zero and negative sectional curvatures are encouraging, as shown in the research article’s result sections. The constant negative, constant positive, and zero sectional curvatures produce hyperbolic, elliptical, and Euclidean geometries. The workspace equation, derived using Lie algebra, defines the parameters of u12, u3, and u4 to obtain the shortest distances in path planning. The geodesic equations determine the shortest distances in the context of Riemann curvature tensor equations. These parameters from the workspace equation (α1, α2, θ1, r1) are used in the geodesic and Riemann curvature tensor equations. The results show that one needs to choose the most convenient parameters of the mechanism for path-planning capabilities. Both the topology of the mechanism, which is 1-S herein and the parameters of the workspaces should be selected for the pre-defined trajectories of the path planning, as shown in the results. The reconfigurable robots have many mechanism topologies to transform.
  • Öğe
    Real time parking space detection system using a pixel-based processing technique
    (Institute of Electrical and Electronics Engineers Inc., 2024) Şener, Berkay; Dinçer, Şerife Esra
    This study proposes a real-time parking space detection using a pixel-based image processing technique. The proposed algorithm detects free spaces in a busy parking place video stream. The performance of the algorithm is compared with CNN algorithm using YOLOv8 software. The detection rate of the developed algorithm is found to be 9% higher than the YOLOv8 classification model with 5 times less error rate. Also, the proposed system missed fewer objects and requires less memory space than the YOLOv8 model.
  • Öğe
    VR-based promotion and training of electric vehicles
    (Institute of Electrical and Electronics Engineers Inc., 2024) Koç, Hamza Eren; Başarslan, Muhammet Sinan; Canlı, Hikmet
    This study presents an innovative application that showcases electric vehicles using Unity-based virtual reality (VR) technology. In addition to acting as a virtual showroom for electric vehicles, this application provides a range of simulation capabilities, including color selection and interior accessories such as steering wheels. Users can gain new experiences in a simulation environment by interacting with customizable features and exploring various aspects of electric vehicles in an immersive setting. This study has brought a new perspective to the automotive industry as a prototype for human-computer interaction (HCI).
  • Öğe
    Investigation of residual stress variation in sequential butt welding and pocket material removal machining processes utilizing pre-stress method: a 3D simulation approach
    (Multidisciplinary Digital Publishing Institute (MDPI), 2024) Çetintav, Işık; Can, Yılmaz; Akkuş, Nihat
    This study investigates the residual stresses arising from welding and machining processes, recognizing their adverse implications in manufacturing. Employing experimental analysis and simulation techniques, the research scrutinizes residual stress alterations resulting from sequential butt welding and subsequent machining. Utilizing MSC Marc Mentat software(version 2016), three-dimensional models are developed to simulate these processes. The finite element model from welding simulation seamlessly integrates into cutting simulations via the pre-state option. The experimental procedures involve 100 × 100 × 10 mm AISI 304 steel plates subjected to sequential welding and machining, with residual stresses measured at each stage. A comparative analysis between experimental and simulation results elucidates variations in residual stresses induced by sequential processes. The study focuses on examining the initial stress state post-welding and numerically assessing stress modifications due to milling. The results suggest minimal material removal insignificantly affects stress distribution and magnitude at the weld centerline. However, increased material removal leads to noticeable changes in through-thickness transverse stress within the weld zone, contrasting with marginal alterations in through-thickness longitudinal stress. Regions distanced from the weld seam show substantial increases in through-thickness longitudinal stress compared to marginal changes in through-thickness transverse stress.
  • Öğe
    Chemical and vibrational criteria for identifying early sèvres factory porcelain productions
    (Multidisciplinary Digital Publishing Institute (MDPI), 2024) Colomban, Philippe; Şimşek Franci, Gülsu; Gerken, Mareike; Gironda, Michele; Mesqui, Viviane
    Thirteen porcelains assigned to Sèvres factory productions and a few references to the other contemporary factories (Chantilly, Limoges, and Venice) have been studied on-site with a portable X-ray fluorescence (pXRF) spectrometer in order to control the provenance attribution. Characteristic XRF signals of major elements (Si, Ca, K, Pb) and minor/trace (Au, Bi, As, Ti, Co, Cu, Zn, Ni, Y, Zr, Rb, and Sr) elements are compared for the paste, blue mark, various glazed (colored) areas, and gilding. The comparison of peak intensities clearly distinguishes different types of hard- and soft-paste porcelain, made from either similar or distinct raw materials. The analysis of transition elements associated with cobalt identifies three types of cobalt blue and reveals that du Barry-style decoration on certain artifacts was typical of 19th-century production. On-site comprehensive studies of the two famous Etruscan-style breast bowls from Rambouillet Castle dairy, using pXRF and Raman spectroscopy, confirm the use of soft-paste porcelain for the cup and hard-paste for its support, providing detailed information on the use of gold nanoparticles in the burgundy-colored decoration.
  • Öğe
    Speed of light in vacuum in the case of arbitrarily non-uniform motion of reference frames
    (IEEE, 2021) Yener, Namık
    Reference frames in arbitrary relative motion and with a coordinate transformation law are considered. It is shown that continuity of the time coordinate of one frame in the time coordinate of the other is a necessity for any physical coordinate transformation even if the velocity function for the relative motion of the reference frames is discontinuous in time. Then the differential Lorentz transform is used to infer an infinite speed of light in vacuum c, when the reference frames are in non-uniform relative motion. Based on the continuity of the time coordinate of one frame on the time coordinate of the other and on the integral representation of the differential Lorentz transform, a set of necessary and sufficient conditions is proved for the attainment of an infinite speed of light for reference frames in arbitrary relative motion. Using these conditions, it can be inferred that an initially finite c can be made infinite if and only if i) the reference frames are initially at rest and their motion, be it uniform rectilinear or arbitrarily non-uniform, starts with an initially discontinuous relative speed v'(x) in time or ii) the frames are in arbitrary motion which at t' = 0 undergoes a jump discontinuity in v'(x) with v'(x) not equal 0 at t' = 0+. After the infinite character of c is attained, c remains infinite regardless of whether the change in v'(x) is smooth or not, until the motion comes to a stop not to start again with another initial discontinuous v'(x). On the other hand, the differential Lorentz transform that holds in the immediate neighborhood of a fiducial observer, is only local and is therefore incapable of allowing drawing of global conclusions directly, such as the globally infinite c result of the paper. However, the proof that c is infinite locally can be generalized to hold for all space coordinates and for all future time, if one observes that unless the motion of the frames comes to a stop not to start again with a discontinuous v'(x) the infinite character of c does not change when immediate neighborhoods of particular observers are jointed to constitute the full space and future time.