Crystallization of Random Metallocene-Catalyzed Propylene-Based Copolymers with Ethylene and 1-Hexene on Rapid Cooling

Propylene-based random copolymers with either ethylene or 1-hexene as comonomer, produced using a metallocene catalyst, were studied regarding their crystallization behaviors, with a focus on rapid cooling. To get an impression of processing effects, fast scanning chip calorimetry (FSC) was used in addition to the characterization of the mechanical performance. When comparing the comonomer type and the relation to commercial grades based on Ziegler–Natta-type catalysts, both an interaction with the catalyst-related regio-defects and a significant difference between ethylene and 1-hexene was observed. A soluble-type nucleating agent was found to modify the behavior, but to an increasingly lesser degree at high cooling rates.

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Caracterização da Peneira Média em Clones de Coffea canephora

REVISTA FIMCA ◽

10.37157/fimca.v5i2.58 ◽

2018 ◽

Vol 5 (2) ◽

pp. 28-31

Author(s):

Darlan Darlan Sanches Barbosa Alves ◽

Victor Mouzinho Spinelli ◽

Marcos Santana Moraes ◽

Carolina Augusto De Souza ◽

Rodrigo da Silva Ribeiro ◽

...

Keyword(s):

Genetic Improvement ◽

Block Design ◽

Coffea Canephora ◽

Coffee Production ◽

Randomized Block Design ◽

Significant Difference ◽

The Mean ◽

Four Blocks ◽

Selection Of

Introdução: O estado de Rondônia se destaca como tradicional produtor de café, sendo o segundo maior produtor brasileiro de C. canephora. No melhoramento genético de C. canephora, a seleção de plantas de elevada peneira média está associada à bebida de qualidade superior. Objetivos: O objetivo desse estudo foi avaliar a variabilidade genética de clones de C. canephora para o tamanho dos grãos, mensurado a partir da avaliação da peneira média (PM). Materiais e Métodos: Para isso, foi conduzido ao longo de dois anos agrícolas experimento no campo experimental da Embrapa no município de Ouro Preto do Oeste-RO, para a avaliação da peneira média de 130 genótipos (clones) com características das variedades botânicas Conilon, Robusta e híbridos intervarietais. O delineamento experimental utilizado foi de blocos ao acaso, com quatro repetições de quatro plantas por parcela. Resultados: Não houve resultados significativos para a interação clones X anos, indicando uma maior consistência no comportamento das plantas ao longo do tempo. Porém foram observadas diferenças significativas para o tamanho dos grãos entre os genótipos avaliados, possibilitando selecionar genótipos superiores. Conclusão: Os genótipos agruparam-se em cinco classes de acordo com o teste de média, subsidiando a caracterização de um gradiente de variabilidade da característica avaliada ABSTRACTIntroduction: Coffea canephora accounts for approximately 35% of the world's coffee production. The state of Rondônia stands out as a traditional coffee producer, being the second largest Brazilian producer of C. canephora. In the classical genetic improvement of C. anephora, the selection of plants of high average sieve is associated with a drink of superior quality. Objectives: The objective of this udy was to evaluate the genetic variability of Coffea canephora clones for the agronomic medium sieve (PM). Materials and Methods: The experiment was conducted in the experimental field of Embrapa, municipality of OuroPreto do Oeste-RO, located at coordinates 10º44'53 "S and 62º12'57". One hundred thirty genotypes (clones) of botanical characteristics Conilon, Robusta and intervarietal hybrids were evaluated in the agricultural years 2013-2014 and 2014-2015. The experimental design was a randomized block design with four blocks and four plants per plot, spacing 3.5 x 1.5 meters between plants. Results: Significant difference was found for the grain size. According to the F test, at 5% probability, the genotypes were grouped into five classes according to the mean test. Conclusion: The results obtained subsidized the characterization of a variability gradient of the evaluated trait.

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A global non-invasive methodology for the phenotyping of potato under water deficit conditions using imaging, physiological and molecular tools

Plant Methods ◽

10.1186/s13007-021-00771-0 ◽

2021 ◽

Vol 17 (1) ◽

Author(s):

M. Musse ◽

G. Hajjar ◽

N. Ali ◽

B. Billiot ◽

G. Joly ◽

...

Keyword(s):

Water Stress ◽

Water Deficit ◽

Soil Conditions ◽

Growth Stages ◽

Dry Matter Content ◽

Tuber Growth ◽

Non Invasive ◽

Potato Plants ◽

Significant Difference

Abstract Background Drought is a major consequence of global heating that has negative impacts on agriculture. Potato is a drought-sensitive crop; tuber growth and dry matter content may both be impacted. Moreover, water deficit can induce physiological disorders such as glassy tubers and internal rust spots. The response of potato plants to drought is complex and can be affected by cultivar type, climatic and soil conditions, and the point at which water stress occurs during growth. The characterization of adaptive responses in plants presents a major phenotyping challenge. There is therefore a demand for the development of non-invasive analytical techniques to improve phenotyping. Results This project aimed to take advantage of innovative approaches in MRI, phenotyping and molecular biology to evaluate the effects of water stress on potato plants during growth. Plants were cultivated in pots under different water conditions. A control group of plants were cultivated under optimal water uptake conditions. Other groups were cultivated under mild and severe water deficiency conditions (40 and 20% of field capacity, respectively) applied at different tuber growth phases (initiation, filling). Water stress was evaluated by monitoring soil water potential. Two fully-equipped imaging cabinets were set up to characterize plant morphology using high definition color cameras (top and side views) and to measure plant stress using RGB cameras. The response of potato plants to water stress depended on the intensity and duration of the stress. Three-dimensional morphological images of the underground organs of potato plants in pots were recorded using a 1.5 T MRI scanner. A significant difference in growth kinetics was observed at the early growth stages between the control and stressed plants. Quantitative PCR analysis was carried out at molecular level on the expression patterns of selected drought-responsive genes. Variations in stress levels were seen to modulate ABA and drought-responsive ABA-dependent and ABA-independent genes. Conclusions This methodology, when applied to the phenotyping of potato under water deficit conditions, provides a quantitative analysis of leaves and tubers properties at microstructural and molecular levels. The approaches thus developed could therefore be effective in the multi-scale characterization of plant response to water stress, from organ development to gene expression.

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Fabrication and characterization of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) modified with nano-montmorillonite biocomposite

e-Polymers ◽

10.1515/epoly-2021-0006 ◽

2020 ◽

Vol 21 (1) ◽

pp. 038-046

Author(s):

Xu Yan ◽

Wanru Zhou ◽

Xiaojun Ma ◽

Binqing Sun

Keyword(s):

Thermal Stability ◽

Oxygen Permeability ◽

Water Vapor Permeability ◽

Barrier Properties ◽

Nucleating Agent ◽

Vapor Permeability ◽

Casting Method ◽

Increasing Trend ◽

Solution Casting Method

Abstract In this study, a poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) modified with nano-montmorillonite biocomposite (MMT/PHBH) was fabricated by solution-casting method. The results showed that the addition of MMT increased the crystallinity and the number of spherulites, which indicated that MMT was an effective nucleating agent for PHBH. The maximum decomposition peak of the biocomposites moved to a high temperature and residue presented an increasing trend. The biocomposites showed the best thermal stability at 1 wt% MMT. Compared with PHBH, 182.5% and 111.2% improvement in elastic modulus and tensile strength were obtained, respectively. Moreover, the oxygen permeability coefficient and the water vapor permeability of MMT/PHBH biocomposites decreased by 43.9% and 6.9%, respectively. It was also found that the simultaneous enhancements on the crystallizing, thermal stability, mechanical, and barrier properties of biocomposites were mainly caused by the formation of intercalated structure between PHBH and MMT.

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Design and Characterization of Microscale Auxetic and Anisotropic Structures Fabricated by Multiphoton Lithography

Nanomaterials ◽

10.3390/nano11020446 ◽

2021 ◽

Vol 11 (2) ◽

pp. 446

Author(s):

Ioannis Spanos ◽

Zacharias Vangelatos ◽

Costas Grigoropoulos ◽

Maria Farsari

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Mechanical Performance ◽

Element Analysis ◽

Mechanical Responses ◽

Multiphoton Lithography ◽

Anisotropic Structures ◽

Scanning Electron

The need for control of the elastic properties of architected materials has been accentuated due to the advances in modelling and characterization. Among the plethora of unconventional mechanical responses, controlled anisotropy and auxeticity have been promulgated as a new avenue in bioengineering applications. This paper aims to delineate the mechanical performance of characteristic auxetic and anisotropic designs fabricated by multiphoton lithography. Through finite element analysis the distinct responses of representative topologies are conveyed. In addition, nanoindentation experiments observed in-situ through scanning electron microscopy enable the validation of the modeling and the observation of the anisotropic or auxetic phenomena. Our results herald how these categories of architected materials can be investigated at the microscale.

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Integration of Dental Implants in Conjunction with EDTA-Conditioned Dentin Grafts: An Experimental Study

Dentistry Journal ◽

10.3390/dj9060063 ◽

2021 ◽

Vol 9 (6) ◽

pp. 63

Author(s):

Payam Farzad ◽

Ted Lundgren ◽

Adel Al-Asfour ◽

Lars Andersson ◽

Christer Dahlin

Keyword(s):

Direct Contact ◽

Mineral Content ◽

X Rays ◽

X Ray ◽

Dentin Surface ◽

Significant Difference ◽

C And N ◽

Micro Implants ◽

Demineralized Dentin

This study was undertaken to investigate the integration of titanium micro-implants installed in conjunction with previously dentin-grafted areas and to study the morphological appearance, mineral content, and healing pattern of xenogenic EDTA-conditioned dentin blocks and granules grafted to cavities in the tibial bone of rabbits. Demineralized and non-demineralized dentin blocks and granules from human premolars were implanted into cavities prepared on the lateral aspects of the tibias of rabbits. After a healing period of six months, micro-implants were installed at each surgical site. Histological examinations were carried out after 24 weeks. Characterization of the EDTA-conditioned dentin blocks was performed by means of light microscopy, dental X-rays, scanning electron microscopy, and energy dispersive X-ray analysis (EDX). No implants were found to be integrated in direct contact with the dentin particles or blocks. On the EDTA-conditioned dentin surface, the organic marker elements C and N dominated, as revealed by EDX. The hydroxyapatite constituents Ca and P were almost absent on the dentin surface. No statistically significant difference was observed between the EDTA-conditioned and non-demineralized dentin, as revealed by BIC and BA. The bone-inductive capacity of the dentin material seemed limited, although demineralization by means of EDTA indicated higher BIC and BA values in conjunction with the installed implants in the area. A 12 h EDTA treatment did not fully decalcify the grafts, as revealed by X-ray analysis.

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Design of a force-measuring setup for colorectal compression anastomosis and first ex-vivo results

International Journal of Computer Assisted Radiology and Surgery ◽

10.1007/s11548-021-02371-8 ◽

2021 ◽

Author(s):

Jana Steger ◽

Isabella Patzke ◽

Maximilian Berlet ◽

Stefanie Ficht ◽

Markus Eblenkamp ◽

...

Keyword(s):

Ex Vivo ◽

Tissue Fixation ◽

Force Transmission ◽

Tissue Thickness ◽

Colon Tissue ◽

Device Development ◽

Compression Anastomosis ◽

Technical Requirements ◽

Significant Difference

Abstract Purpose The introduction of novel endoscopic instruments is essential to reduce trauma in visceral surgery. However, endoscopic device development is hampered by challenges in respecting the dimensional restrictions, due to the narrow access route, and by achieving adequate force transmission. As the overall goal of our research is the development of a patient adaptable, endoscopic anastomosis manipulator, biomechanical and size-related characterization of gastrointestinal organs are needed to determine technical requirements and thresholds to define functional design and load-compatible dimensioning of devices. Methods We built an experimental setup to measure colon tissue compression piercing forces. We tested 54 parameter sets, including variations of three tissue fixation configurations, three piercing body configurations (four, eight, twelve spikes) and insertion trajectories of constant velocities (5 mms−1, 10 mms−1,15 mms−1) and constant accelerations (5 mms−2, 10 mms−2, 15 mms−2) each in 5 samples. Furthermore, anatomical parameters (lumen diameter, tissue thickness) were recorded. Results There was no statistically significant difference in insertion forces neither between the trajectory groups, nor for variation of tissue fixation configurations. However, we observed a statistically significant increase in insertion forces for increasing number of spikes. The maximum mean peak forces for four, eight and twelve spikes were 6.4 ± 1.5 N, 13.6 ± 1.4 N and 21.7 ± 5.8 N, respectively. The 5th percentile of specimen lumen diameters and pierced tissue thickness were 24.1 mm and 2.8 mm, and the 95th percentiles 40.1 mm and 4.8 mm, respectively. Conclusion The setup enabled reliable biomechanical characterization of colon material, on the base of which design specifications for an endoscopic anastomosis device were derived. The axial implant closure unit must enable axial force transmission of at least 28 N (22 ± 6 N). Implant and applicator diameters must cover a range between 24 and 40 mm, and the implant gap, compressing anastomosed tissue, between 2 and 5 mm.

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A Comprehensive Investigation on 3D Printing of Polyamide 11 and Thermoplastic Polyurethane via Multi Jet Fusion

Polymers ◽

10.3390/polym13132139 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2139

Author(s):

Wei Shian Tey ◽

Chao Cai ◽

Kun Zhou

Keyword(s):

Tensile Strength ◽

Flexural Strength ◽

Wear Rate ◽

Mechanical Performance ◽

Thermoplastic Polyurethane ◽

Print Quality ◽

Polyamide 11 ◽

Powder Bed

Multi Jet Fusion (MJF) is a recently developed polymeric powder bed fusion (PBF) additive manufacturing technique that has received considerable attention in the industrial and scientific community due to its ability to fabricate functional and complex polymeric parts efficiently. In this work, a systematic characterization of the physicochemical properties of MJF-certified polyamide 11 (PA11) and thermoplastic polyurethane (TPU) powder was conducted. The mechanical performance and print quality of the specimens printed using both powders were then evaluated. Both PA11 and TPU powders showed irregular morphology with sharp features and had broad particle size distribution, but such features did not impair their printability significantly. According to the DSC scans, the PA11 specimen exhibited two endothermic peaks, while the TPU specimen exhibited a broad endothermic peak (116–150 °C). The PA11 specimens possessed the highest tensile strength in the Z orientation, as opposed to the TPU specimens which possessed the lowest tensile strength along the same orientation. The flexural properties of the PA11 and TPU specimens displayed a similar anisotropy where the flexural strength was highest in the Z orientation and lowest in the X orientation. The porosity values of both the PA11 and the TPU specimens were observed to be the lowest in the Z orientation and highest in the X orientation, which was the opposite of the trend observed for the flexural strength of the specimens. The PA11 specimen possessed a low coefficient of friction (COF) of 0.13 and wear rate of 8.68 × 10−5 mm3/Nm as compared to the TPU specimen, which had a COF of 0.55 and wear rate of 0.012 mm3/Nm. The PA11 specimens generally had lower roughness values on their surfaces (Ra < 25 μm), while the TPU specimens had much rougher surfaces (Ra > 40 μm). This investigation aims to uncover and explain phenomena that are unique to the MJF process of PA11 and TPU while also serving as a benchmark against similar polymeric parts printed using other PBF processes.

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Poultry Production in Nepal: Characteristics, Productivity and Constraints

International Journal of Applied Sciences and Biotechnology ◽

10.3126/ijasbt.v5i2.17616 ◽

2017 ◽

Vol 5 (2) ◽

pp. 222-226 ◽

Cited By ~ 1

Author(s):

Rajani Osti ◽

Dinesh Bhattarai ◽

Harshika Chaudhary ◽

Virendra Singh

Keyword(s):

Egg Production ◽

Marketing Channel ◽

Site Investigation ◽

Chronic Respiratory Disease ◽

Poultry Production ◽

Poultry Products ◽

Significant Difference ◽

Ranking Technique ◽

Poultry Farming

Poultry farming is integral part of agriculture in Nepal. The objective of this research was to analyze the prevailing production constraints, characterization of poultry farming and its economic analysis using questionnaire-based survey and on-site investigation. 180 farms were selected from 3 major districts. Garrett’s ranking technique was used to analyze the constraints. Highly significant difference (P<0.01) in size of poultry farm was found. We found significant difference in feeding, housing and drinking system for the chicken. Un-organized chicken marketing channel was observed in the study area. High chicks’ mortality, wastage of feed, insecure vaccination and frequent drop in egg production were characteristic of laying hens. Newcastle disease and Chronic Respiratory Disease were acknowledged as the biggest constraint of chicken production. Government and concerned agencies need to take active part for the extension service to strengthen the health of chicken and organized marketing channel is essential for selling of poultry products which can improve the profit to the farmers.Int. J. Appl. Sci. Biotechnol. Vol 5(2): 222-226

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Characterization of mechanical performance of Sn/Ag/Cu solder joints with different component lead coatings

Soldering & Surface Mount Technology ◽

10.1108/09540910410517031 ◽

2004 ◽

Vol 16 (1) ◽

pp. 35-43 ◽

Cited By ~ 4

Author(s):

Minna Arra ◽

Todd Castello ◽

Dongkai Shangguan ◽

Eero Ristolainen

Keyword(s):

Solder Joints ◽

Mechanical Performance

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Multiblock Copolymers of Norbornene and Cyclododecene: Chain Structure and Properties

Polymers ◽

10.3390/polym13111756 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1756

Author(s):

Yulia I. Denisova ◽

Georgiy A. Shandryuk ◽

Marianna P. Arinina ◽

Ivan S. Levin ◽

Vsevolod A. Zhigarev ◽

...

Keyword(s):

First Generation ◽

Average Length ◽

Chain Structure ◽

Random Copolymers ◽

Multiblock Copolymers ◽

Structure Property ◽

Reaction Conditions ◽

Property Relations ◽

Cross Metathesis

We investigate the structure–property relations of the multiblock copolymers of norbornene with cyclododecene synthesized via the macromolecular cross-metathesis reaction between amorphous polynorbornene and semicrystalline polydodecenamer in the presence of the first-generation Grubbs catalyst. By adjusting the reaction time, catalyst amount, and composition of the initial system, we obtain a set of statistical multiblock copolymers that differ in the composition and average length of norbornene and dodecenylene unit sequences. Structural, thermal, and mechanical characterization of the copolymers with NMR, XRD, DSC (including thermal fractionation by successive self-nucleation and annealing), and rotational rheology allows us to relate the reaction conditions to the average length of crystallizable unit sequences, thicknesses of corresponding lamellas, and temperatures of their melting. We demonstrate that isolated dodecenylene units can be incorporated into crystalline lamellas so that even nearly random copolymers should retain crystallinity. Weak high-temperature endotherms observed in the multiblock copolymers of norbornene with cyclododecene and other cycloolefins could indicate that the corresponding systems are microphase-separated in the melt state.

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