A Study on the Modeling and Simulation of Bio-inspired Hedgehog Spines Structures for More Efficient Use Digital Manufacturing Processes

Direct digital manufacture and additive manufacture have allowed designers the ability to design components without the design limitations witnessed in subtractive manufacturing process routes. In particular, designers can now design parts that fully utilize material usage resulting in a more sustainable and environmentally friendly application of manufacturing technology. Within this context, designing and manufacturing bio-inspired components have the potential to increase both component functionality and optimize material usage. One such area of biomimicry with advantageous strength-to-weight ratio can be found in hedgehog spines. Within this study, hedgehog spines were redesigned to facilitate production through additive manufacture. In addition, with the use of finite element analysis to quantify the resulting compressive characteristics, the optimal internal geometry and septa spacing were determined. Also, a design of experiments study was conducted to determine which design features have the greatest influence on the resulting stress in the spine. The analysis concluded that the combination of longitudinal stiffeners and equally spaced septa give the spine its superior compressive strength

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Lightweight passenger seat design and prototype production for next generation commercial vehicles

Günümüzde taşıtlarda yakıt tasarrufu hem maliyet hem de emisyon oranlarına getirilen kısıtlamalardan dolayı zorunlu hale gelmiştir. Bu doğrultuda enerji verimliliğini arttıracak, emisyon oranlarını azaltacak bir çok teknoloji geliştirilmektedir. Bu teknolojiler arasında taşıt ağırlığını hafifletme ön plana çıkmaktadır. Yolcu koltukları özellikle toplu taşıma araçlarının ağırlıklarında sayıları itibariyle önemli bir yer tutmaktadır. Bu çalışmada ticari araçlarda kullanılmak üzere hafifletilmiş yolcu koltuğu tasarımı ve prototip imalatı gerçekleştirilmiştir. Geleneksel koltuk yapısında kullanılan St-37 çelik malzemeden üretilmiş boru ve profillerin yerine yüksek mukavemetli çelik malzemeden üretilmiş parçalar kullanılmıştır. Tasarım aşamasında TRIZ problem çözme metodundan faydalanılmıştır. Hafifletme amacıyla yüksek mukavemetli çelikten üretilmiş profillerin kalınlıkları sonlu elemanlar yöntemi ile yapılan analizler sonucunda belirlenmiştir. Kalınlıkları belirlenen profillerden yolcu koltuğunun prototip üretimi gerçekleştirilmiş ve ECE güvenlik standartlarına uygun olarak testleri yapılmıştır. Çalışma sonucunda geleneksel koltuk yapısından yaklaşık %20 oranında daha hafif bir yolcu koltuğu üretilmiş ve ortaya çıkan prototip koltuk M3 ve M2 sınıfı ticari araçlar için belirlenmiş olan güvenlik standartlarını sağlamıştır.Currently fuel saving has become mandatory for vehicles due to both cost and restrictions of the emission rates. In this respect various technology is being developed to reduce emissions and improve energy efficiency. Weight reduction is come to the fore through these technologies. Passenger seats are one of the major contributors of the total vehicle weight especially in mass transit vehicles. In this study, lightweight passenger seat design and prototype manufacturing for commercial vehicles was conducted. Conventional seat structure made of ST-37 steel tubes and profiles instead of this new components which made of high strength steel was used. TRIZ problem solving method have been used at the design stage. High strength steel profiles thickness were determined as a result of the analysis by finite element method. Prototype passenger seat was made of defined profiles thickness. The new seat have been tested in accordance with ECE safety standards. As a result of the study, a passenger seat was manufactured approximately 20% lighter than conventional seat structure and this new structure ensured safety standarts which are set for the M2 and M3 vehicle class.T.C. Bilim, Sanayi ve Teknoloji Bakanlığı Bilim ve Teknoloji Genel Müdürlüğü San-Tez Projesi 01494.STZ.2012-

Biomimetics: its practice and theory

Biomimetics, a name coined by Otto Schmitt in the 1950s for the transfer of ideas and analogues from biology to technology, has produced some significant and successful devices and concepts in the past 50 years, but is still empirical. We show that TRIZ, the Russian system of problem solving, can be adapted to illuminate and manipulate this process of transfer. Analysis using TRIZ shows that there is only 12% similarity between biology and technology in the principles which solutions to problems illustrate, and while technology solves problems largely by manipulating usage of energy, biology uses information and structure, two factors largely ignored by technology

Freeze-out radii extracted from three-pion cumulants in pp, p–Pb and Pb–Pb collisions at the LHC

In high-energy collisions, the spatio-temporal size of the particle production region can be measured using the Bose-Einstein correlations of identical bosons at low relative momentum. The source radii are typically extracted using two-pion correlations, and characterize the system at the last stage of interaction, called kinetic freeze-out. In low-multiplicity collisions, unlike in high-multiplicity collisions, two-pion correlations are substantially altered by background correlations, e.g. mini-jets. Such correlations can be suppressed using three-pion cumulant correlations. We present the first measurements of the size of the system at freeze-out extracted from three-pion cumulant correlations in pp, p-Pb and Pb-Pb collisions at the LHC with ALICE. At similar multiplicity, the invariant radii extracted in p-Pb collisions are found to be 5-15% larger than those in pp, while those in Pb-Pb are 35-55% larger than those in p-Pb. Our measurements disfavor models which incorporate substantially stronger collective expansion in p-Pb as compared to pp collisions at similar multiplicity