No / The study is based on a previously proposed methodology for multiaxial fatigue life assessment of injection-molded components (called ‘Through Process Modeling’ (TPM)). The present contribution focuses on stress concentration effects induced in notched samples. Purely macroscopic approaches are unable to capture the different mechanical responses of variably injected parts with the same shape. A high interest of the present method is to take into account the difference of fiber orientation resulting from the process. After briefly reminding the TPM method, it will be shown that good lifetime estimations are obtained for laterally injected samples, from a fatigue criterion identification based on longitudinally injected ones.

Since the first successful derivation of human embryonic stem cells (hESC), rapid progress has been attained in the development of strategies in differentiation of these cells into various neural lineages, with the fundamental objective of using these cells for replacement and repair of damaged neuronal circuits in the central nervous system (CNS). Of particular interest are midbrain dopaminergic (mDA) neurons, which play a central role in regulation of voluntary movement. Degeneration or loss of function of mDA neurons in the nigrostriatal pathway is associated with Parkinson disease (PD). Stromal-Derived Inducing Activity (SDIA) is recognized as one of the most efficient methods in restricting ESC differentiation to a dopaminergic lineage, and refers to the property of mouse stromal cell lines such as PA6 or MS5 to cause ESC to differentiate to DA neurons. Although this strategy has been extensively used to generate mDA neurons from hESC, the biochemical nature of SDIA is yet unknown.  In the present study mDA neurons were generated from the BG01V2 hESC line by SDIA. To examine whether SDIA exerts its effect directly on hESC and is responsible for early dopaminergic induction, neural progenitor cells (NPC) were enyzmatically isolated from the co-cultures and allowed to differentiate in feeder-free conditions. The isolated cells were committed to a mesencephalic neural lineage, and were capable of maintaining their phenotype and developing into postmitotic mDA neurons in feeder-free conditions. The mDA neurons showed neuronal excitability and dopamine transporter function. The in vitro proliferation and differentiation of the NPC was also investigated by a BrDU incorporation assay. Next, the maintenance of cellular memory and capacity for proliferation of the mesencephalic NPC was assessed. The NPC could be expanded in vitro by five-fold as neurospheres for up to two weeks while retaining their DA differentiation potential, but did not retain a stable phenotype over extended periods of time. Preliminary transplantation experiments of neurospheres in striatal lesioned animals indicated, however, that these cells could survive and conserve their phenotype in vivo. To gain additional insight into the biochemical role of SDIA in early dopaminergic induction of hESC, the separate contributions of cell surface activity and secreted factors were examined. The data revealed that the PA6 cell surface activity promoted cell survival and was mainly responsible for enhanced neurogenesis of hESC, whereas secreted factors provided DA lineage-specific instructions. In order to identify the soluble factors responsible for the DA phenotype-inducing component of SDIA, the gene expression profile of PA6 cells was compared to that of cell lines lacking the DA-inducing property. A number of soluble factors known to be associated with CNS development that were highly expressed in PA6 cells were identified as potential DA differentiation-inducing candidates. These differentially-expressed genes included stromal cell-derived factor 1 (SDF-1/CXCL12), pleiotrophin (PTN), insulin-like growth factor 2 (IGF2), and ephrin B1 (EFNB1). When these factors, termed SPIE, were applied to the hESC, they induced dopaminergic neuronal differentiation of hESC line, BG01V2 and other karyotypically normal hESC lines in vitro. Thus, it appears that SPIE comprises the DA phenotype-inducing property of SDIA. This may provide a simple and direct means of differentiating hESC to form DA neurons in a single step, without a requirement for co-culture, animal cell lines, or animal products. / QC 20100916

The objective of this study is to synthesize nematic-thermotropic liquid crystalline polymers (LCP) and determine their possible application areas. In this context, thirty different LCP&rsquo / s were synthesized and categorized with respect to their fiber formation capacity, melting temperature and mechanical properties. The basic chemical structure of synthesized LCP&rsquo / s were composed of p-acetoxybenzoic acid (p-ABA), m-acetoxybenzoic acid (m-ABA), hydroquinone diacetate (HQDA), terephthalic acid (TPA) and isophthalic acid (IPA) and alkyl-diacids monomers. In addition to mentioned monomers, polymers and oligomers were included in the backbone such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) polymers, and polybutylene naphthalate (PBN), polyhexylene naphthalate (PHN) and poly butylene terephthalate (PBT) oligomers that contain different kinds of alkyl-diols. We adjusted the LCP content to have low melting point (180oC-280oC) that is processable with thermoplastics. This was achieved by balancing the amount of linear (para) and angular (meta) groups on the aromatic backbones together with the use of linear hydrocarbon linkages in the random copolymerization (esterification) reaction. LCP species were characterized by the following techniques / Polarized Light Microscopy, Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Analysis (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), X-ray Scattering (WAXS, Fiber diffraction), surface free energy, end group analysis (CEG), intrinsic viscosity (IV) and tensile test. According to these analysis LCPs were classified into five main categories / (I) fully aromatics, (II) aromatics+ PET/PEN, (III) aromatics + oligomers (IV) aromatics + short aliphatic diacids, (V) aromatics + long aliphatic diacids. The foremost results of the analysis can be given as below. DSC analysis shows that some LCPs are materials that have stable LC mesogens under polarized light microscopy. In TGA analysis LCPs that have film formation capacity passed the thermal stability test up to 390oC. NMR results proved that predicted structures of LCPs from feed charged to the reactor are correct. In FTIR due to the inclusion of new moieties, several peaks were labeled in the finger-print range that belongs to reactants. In X-ray analysis, LCP24 (containing PET) was found to be more crystalline than LCP25 (containing PEN) which is due to the symmetrical configuration. Block segments were more pronounced in wholly aromatic LCP2 than LCP24 that has flexible spacers. Another important finding is that, as the amount of the charge to the reactor increases CEG value increases and molecular weight of the product decreases. Selected group V species were employed as reinforcing agent and mixed with the thermoplastics / acrylonitrile butadiene styrene (ABS), nylon6 (PA6), polyethylene terephthalate (PET), polypropylene (PP) and appropriate compatibilizers in micro compounder and twin screw extruder. The blends of them were tested in dog-bone and/or fiber form. In general LCPs do not improve the mechanical properties except in composite application with polypropylene. A significant increase in tensile properties is observed by LCP24 and LCP25 usage. Capillary rheometer studies show that the viscosity of ABS decreases with the inclusion PA6 and LCP2 together. In addition to the composite applications, some LCPs are promising with new usage areas. Such as nano fibers with 200nm diameter were obtained from LCP27 by electrospinning method. The high dielectric constant of LCP29 has shown that it may have application areas in capacitors.

Water Stuff & Sun are developing a hydrogen battery based on a technology called SFEER’s. The SFEER’s are spherical high-pressure gas storage containers that are the size of a tennis ball. They consist of a carbon fiber-shell that is lined on the inside with a polymer called PA6. The aim of this literature review is to present suitable materials that can be utilized as a coating on the PA6 liner in the SFEER’s to minimize the hydrogen permeability. The metallic coatings that were investigated are compounds based on chromium, boron, alu- minum and titanium. The non-metallic coatings that were investigated are lamellar inorganic components (LIC) in combination with PA6 and modified graphene oxide (GO). The coating methods that were investigated are some different PVD and CVD methods (sputter deposition, plasma enhanced CVD, ALD), electrodeposition and cold spray. The lowest permeability out of all the coatings was observed for alumina, Al2O3. Titanium nitride, TiN, was also found to have very low permeability. Since these two coatings had the lowest permeabilities they were further compared considering other factors. This resulted in alumina being chosen as the final recommendation for coating the SFEER’s. A comparison was also made to find the most suitable coating method for alumina. Cold spray was found to be very promising but if it can not be used the PVD and CVD methods are other potential candidates.

Rapporten avser ett produktutvecklingsprojekt hos ett företag. Företaget har ett problem avseende kontaktering i deras handhållna batteridrivna produkter, problemet har varit aktuellt att lösa under längre tid. Problemet yttrar sig i form av diverse olika tekniska, elrelaterade, sporadiska fel till följd av tillverkningsteknikens begränsningar i form av toleranssättning. När fullgod kontaktering (fullständigt hoptryckta kontaktdon) inte uppnås resulterar det också i att batteriet inte sitter helt inspänt och konstruktionen upplevs som racklig vilket minskar kvalitetsintrycket av produkten i sin helhet. Företaget kan, med modern tillverkningsteknik, inte garantera att batteriet placeras in i deras produkter på ett sätt som leder till fullgod kontaktering. Eftersom nolltolerans för variation i distanser och geometrier från produktion inte är realistiskt behöver företaget en ny konceptinriktning som tillåter normala avvikelser utan att skapa elektriska problem. Projektet har haft snäva ramar, krav och avgränsningar som har krävt en metodisk produktutvecklingsprocess. Kravbilden innefattar total kompabilitet med samtliga batterier i produktsortimentet, kontaktering med nolldistans i gränssnittet mellan produkt och batteri samt potential för fullständig universalitet i företagets olika produkter. Lösningen får dessutom inte öka komponentantalet eller monteringstiden avsevärt. Lösningen som tagits fram klarar variationer i distanser upp till fem millimeter och tillåter en svarande linjär rörelse i samband med placering av batteri. Oavsett vilka distanser, från det produktions tolererade intervallet, som en given produkt besitter uppnås fullgod kontaktering och batteriet spänns fast vilket minskar spel i placering av batteriet och ökar kvalitetsintrycket. Projektets ramar ledde till en lösning som både är kompakt och kan platsa i hela det handhållna sortimentet och som är fullständigt universell. Företaget har visat stort intresse för lösningen som anses besitta potential och lösningen kan komma att implementeras i företagets produktsortiment. / This paper describes a product development project at a company. The company has a technical issue regarding connection between the battery and a given unit in their handheld electrical range of products. The problem consists of a range of sporadic, technical electrical issues because of the inherent limitations of the manufacturing processes due to tolerance of variations in the produced units and it has been relevant to solve for some time. When the connection between a product and its battery isn’t apposite it results in a rattling battery which makes for a less appealing product. Modern methods of manufacturing don’t allow zero tolerance for variation from production and so, the company needs a new direction that allows for normal variations without them causing various electrical issues. The project has been affected by strict requirements and demarcations that have made for a strict, methodical product development approach.The requirements consist of an absolute compatibility with the range of batteries used with the Company’s handheld electrical products, connection with a zero-tolerance distance in the interface between the product and the battery and the potential for universal implementation in the Company’s various products. The resulting system is also not allowed to increase the number of components, or the time spent assembling the units in a substantial way. The resulting system developed can accommodate variations of a magnitude of five millimetres and allows a responsive linear movement when a battery is placed in its socket. Regardless of the magnitude of tolerated variations from production, the solution allows for a zero-distance connection in the interface between the battery and the unit. The system also holds the battery in place which diminishes the battery rattling and improves the impression of the products quality. The framework of the project led to a solution that can fit in the entire handheld product range meaning the solution is fully universal. The company has shown interest for the system and considers it to have potential for future implementation.

In response to the growing concerns surrounding pollution and sustainability, this research explores the possibility of recycling post-consumer polyester (PET) and nylon (PA6) waste for textile applications. By blending the polymers and analyzing the recyclability and thermomechanical properties of PET/PA6 blends, this study aims to contribute to the development of sustainable materials for textile applications. Virgin PET and PA6 polymers were utilized, with blending ratios ranging from 35% PET to 65% PET to assess the impact of composition on the material’s performance. Compounding and injection molding techniques were employed to prepare samples for characterization. Mechanical testing revealed that the blending of PET and PA6 increased tensile and flexural strengths, with higher PET content leading to increased stiffness. However, impact testing indicated a decrease in toughness with the incorporation of PET, which is attributed to increased crystallinity. Thermal analysis demonstrated that the blends retained sufficient thermal stability for industrial processing, despite slight reductions in degradation temperatures. Differential scanning calorimetry explained the crystallization behavior of the blends, revealing nuanced changes in PET's crystallization temperature. The dynamic mechanical analysis highlighted enhanced elastic modulus and improved rigidity and adhesion. These findings may have significant implications for polymer blend research and applications. Understanding the mechanical and thermal behavior of PET/PA6 blends is crucial for optimizing their performance in textiles and various other sectors. The study contributes to the development of sustainable materials with improved mechanical properties, offering potential solutions to environmental challenges and promoting the adoption of recyclable polymers in society. Future research should focus on optimizing blend compositions with compatibilizers to enhance impact strength and fully integrate these materials into textile production processes.

Polymer nanofibers used for the construction of triboelectric nanogenerator (TENG) and piezoelectric nanogenerator (PENG) are new and promising technologies for energy recovery. Thanks to the generation of electrical energy based on mechanical movement (deformation), these fibers can find application in the field of self-powered electronic devices. In this work, three nanofibrous structures of materials were prepared by electrostatic spinning: pure polyvinylidene fluoride (PVDF), pure polyamide-6 (PA6) and their mixed combination PVDF / PA6. Non-destructive analyzes such as Raman spectroscopy, FTIR, XPS and electron microscopy were used to study the properties of nanofibers. Analyzes confirmed the positive effect of electrostatic spinning of polymers on the support of the formation of highly polar crystalline -phase in PVDF and , -phase in PA6. The structure arrangement of the nanofibrous material and their defects were observed by scanning electron microscopy (SEM). Furthermore, the contact angle of the wettability of the liquid on the surface was measured for the materials, and the permittivity was measured to monitor the dielectric properties. The described results make the mixed material PVDF / PA6 very promising for further research in the field of nanogenerators and functional textiles.