scholarly journals High-conductivity flexible Ag films formed by low-temperature and short-time sintering of PVP-modified silver oxalate composite ink

2022 ◽  
Author(s):  
PeiYuan Fan ◽  
WenHua Zhang ◽  
Xianglei Yu ◽  
GuoYou Gan
Keyword(s):  
Electrical Conductivity ◽  
Low Temperature ◽  
Flexible Electronics ◽  
Production Efficiency ◽  
Silver Film ◽  
Sintering Temperature ◽  
Positive Influence ◽  
Complexing Agent ◽  
Silver Oxalate ◽  
The Impact

Abstract Attaining low-temperature sintering and high electrical conductivity is vital in the field of flexible electronics. Inks with silver oxalate as the precursor have recently received significant attention in this field; however, the high sintering temperature and long sintering time limit commercial applicability. High sintering temperature can shorten the sintering timereducing the conductivity. but lead to porous and uneven filmOn the other hand, morphology;low sintering temperature prolongthus,s thesintering time; thus, reducing the production efficiency. To solve the abovementionedproblems, a silver composite conductive ink modified by polyvinylpyrrolidone (PVP)was prepared in this study. The ink used silver oxalate as the precursor, methanol and acetone as the solvent, and 1, 2-diaminopropane as the complexing agent, and could reduce the sintering temperature and time to 160℃ and 20 min, respectively. After sintering, the silver film showed good electrical conductivity, and low resistivity (4.56 μΩ·cm). Furthermore, the impact of sintering temperature on the surface morphology and electrical conductivity were also studied, and the results showed that PVP had a positive influence on the nucleation of silver and the microstructure of the sintered silver film.

scholarly journals Microstructure and properties of a vacuum tempered glass with low-temperature sintered silver paste

2021 ◽  
Author(s):  
Qin Sun ◽  
Guoji Sun ◽  
Yihan Liu ◽  
Yufeng Li ◽  
Hongtao Chen ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Low Temperature ◽  
Glass Powder ◽  
Silver Film ◽  
Sintering Temperature ◽  
Fracture Mechanisms ◽  
Tempered Glass ◽  
Silver Paste ◽  
Dissolution And Precipitation ◽  
Sintered Silver

Abstract A low-temperature sintered silver paste was used for metallization on tempered glass to prepare a vacuum tempered glass by soldering with Sn 96.5 Ag 3 Cu 0.5 paste (SAC305). The effects of the glass content and the sintering temperature on the microstructures, shear strengths, and fracture mechanisms of the bondlines were investigated in detail. The microstructure of the thick silver film and its interface with the tempered glass was characterized. The dissolution and precipitation behaviors of the silver in Bi-B-Zn glass were also analyzed. Bi 4 B 2 O 9 crystals were detected in the microstructure of the thick silver film when the joining temperature was increased above 450 °C, which can strengthen the silver film and the interface with the tempered glass. After soldering at 450 °C for 10 min, an excellent bondline was formed with a shear strength of 42.3 MPa and a leak rate of 7.2 × 10 -3 Pa.cm 3 /s by using the low-temperature sintered paste, which had a composition of 80 wt.% silver and 20 wt.% glass powder. Furthermore, heat transfer tests revealed that the vacuum tempered glass had excellent thermal insulation properties. The results showed that the low-temperature sintered silver paste combined with soldering was an effective method to prepare vacuum tempered glass.

scholarly journals Effect of SWCNT-Tuball Paper on the Lightning Strike Protection of CFRPs and Their Selected Mechanical Properties

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3140
Author(s):  
Kamil Dydek ◽  
Anna Boczkowska ◽  
Rafał Kozera ◽  
Paweł Durałek ◽  
Łukasz Sarniak ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Copper Foil ◽  
Impact Resistance ◽  
Mechanical Analysis ◽  
Lightning Strike ◽  
Single Wall Carbon Nanotubes ◽  
Carbon Fibre Reinforced Polymer ◽  
The Impact

The main aim of this work was the investigation of the possibility of replacing the heavy metallic meshes applied onto the composite structure in airplanes for lightning strike protection with a thin film of Tuball single-wall carbon nanotubes in the form of ultra-light, conductive paper. The Tuball paper studied contained 75 wt% or 90 wt% of carbon nanotubes and was applied on the top of carbon fibre reinforced polymer before fabrication of flat panels. First, the electrical conductivity, impact resistance and thermo-mechanical properties of modified laminates were measured and compared with the reference values. Then, flat panels with selected Tuball paper, expanded copper foil and reference panels were fabricated for lightning strike tests. The effectiveness of lightning strike protection was evaluated by using the ultrasonic phased-array technique. It was found that the introduction of Tuball paper on the laminates surface improved both the surface and the volume electrical conductivity by 8800% and 300%, respectively. The impact resistance was tested in two directions, perpendicular and parallel to the carbon fibres, and the values increased by 9.8% and 44%, respectively. The dynamic thermo-mechanical analysis showed higher stiffness and a slight increase in glass transition temperature of the modified laminates. Ultrasonic investigation after lightning strike tests showed that the effectiveness of Tuball paper is comparable to expanded copper foil.

scholarly journals Foreign investment in emerging legal medicinal cannabis markets: the Jamaica case study

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Marta Rychert ◽  
Machel Anthony Emanuel ◽  
Chris Wilkins
Keyword(s):  
Civil Society ◽  
Foreign Investment ◽  
Production Efficiency ◽  
Production Quality ◽  
Small Scale ◽  
Organic Cultivation ◽  
Enhanced Production ◽  
Political Interference ◽  
Medicinal Cannabis ◽  
The Impact

Abstract Introduction The establishment of a legal market for medicinal cannabis under the Dangerous Drugs Amendment Act 2015 has positioned Jamaica at the forefront of cannabis law reform in the developing world. Many local cannabis businesses have attracted investment from overseas, including from Canada, US and Europe. Aim To explore the opportunities and risks of foreign investment in an emerging domestic legal cannabis market in a developing country. Methods Thematic analysis of semi-structured face-to-face interviews with 22 key informants (KIs) from the Jamaican government, local cannabis industry, academia and civil society, and field observations of legal and illegal cannabis cultivators. Results KIs from the Jamaican public agencies and domestic cannabis entrepreneurs saw foreign investment as an essential source of capital to finance the start-up costs of legal cannabis businesses. Local cannabis entrepreneurs prioritised investors with the greatest financial resources, brand reputation and export networks. They also considered how allied an investor was with their business vision (e.g., organic cultivation, medical vs. recreational). The key benefits of partnering with a foreign investor included transfer of technical knowledge and financial capital, which enhanced production, quality assurance and seed-to-sale tracking. Some KIs expressed concern over investors’ focus on increasing production efficiency and scale at the expense of funding research and development (R&D) and clinical trials. KIs from the local industry, government agencies and civil society highlighted the risks of ‘predatory’ shareholder agreements and domestic political interference. Concerns were raised about the impact of foreign investment on the diversity of the domestic cannabis sector in Jamaica, including the commitment to transition traditional illegal small-scale cannabis cultivators to the legal sector. Conclusion While foreign investment has facilitated the commercialisation of the cannabis sector in Jamaica, regulatory measures are also needed to protect the domestic industry and support the transition of small-scale illegal cultivators to the legal regime. Foreign investments may alter the economic, social and political determinants of health in transitioning from illegal to legal cannabis market economy.

scholarly journals Ag/VO2/Ag sandwich nylon film for smart thermal management and thermo-responsive electrical conductivity

2021 ◽  
pp. 152808372098654
Author(s):  
Linghui Peng ◽  
Lingling Shen ◽  
Weiren Fan ◽  
Zichuan Liu ◽  
Hongbo Qiu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Thermal Comfort ◽  
Thermal Management ◽  
Flexible Electronics ◽  
Sandwich Structure ◽  
Outdoor Thermal Comfort ◽  
Ir Radiation ◽  
Indoor Space ◽  
Layer Structures ◽  
Radiation Management

Due to the effects of climate changing, the importance of outdoor thermal comfort has been recognized, and has gained more and more research attentions. Unlike indoor space where air conditioning can be easily implemented, outdoor thermal comfort can only be achieved by localized thermal management. Using textile is a simple but energy-saving way to realize outdoor thermal comfort. Herein, we report the design of a smart thermal management film with the silver/vanadium dioxide/silver (Ag/VO2/Ag) sandwich structure prepared by one-dimensional (1 D) nanowires. It was found that the Ag/VO2/Ag sandwich film was able to lower the temperature by around 10 °C under intense infrared (IR) radiation. In addition, the Ag/VO2/Ag sandwich structure film showed a thermo-responsive electrical conductivity and an outstanding bending stability, due to network structure formed by nanowires. It was experimentally proved that this sandwich structure was superior to other layer structures in IR shielding performance and thermo-responsive electrical conductivity. The as-prepared Ag/VO2/Ag sandwich structure film has great potential for various applications such as wearable devices, flexible electronics, medical monitors and smart IR radiation management.

scholarly journals Innovations in anaerobic digestion: a model-based study

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Karol Postawa ◽  
Jerzy Szczygieł ◽  
Marek Kułażyński
Keyword(s):  
Mathematical Model ◽  
Anaerobic Digestion ◽  
Production Efficiency ◽  
Biogas Production ◽  
Biogas Plant ◽  
Methane Content ◽  
Pig Manure ◽  
Pig Slurry ◽  
Production Chain ◽  
The Impact

Abstract Background Increasing the efficiency of the biogas production process is possible by modifying the technological installations of the biogas plant. In this study, specific solutions based on a mathematical model that lead to favorable results were proposed. Three configurations were considered: classical anaerobic digestion (AD) and its two modifications, two-phase AD (TPAD) and autogenerative high-pressure digestion (AHPD). The model has been validated based on measurements from a biogas plant located in Poland. Afterward, the TPAD and AHPD concepts were numerically tested for the same volume and feeding conditions. Results The TPAD system increased the overall biogas production from 9.06 to 9.59%, depending on the feedstock composition, while the content of methane was slightly lower in the whole production chain. On the other hand, the AHPD provided the best purity of the produced fuel, in which a methane content value of 82.13% was reached. At the same time, the overpressure leads to a decrease of around 7.5% in the volumetric production efficiency. The study indicated that the dilution of maize silage with pig manure, instead of water, can have significant benefits in the selected configurations. The content of pig slurry strengthens the impact of the selected process modifications—in the first case, by increasing the production efficiency, and in the second, by improving the methane content in the biogas. Conclusions The proposed mathematical model of the AD process proved to be a valuable tool for the description and design of biogas plant. The analysis shows that the overall impact of the presented process modifications is mutually opposite. The feedstock composition has a moderate and unsteady impact on the production profile, in the tested modifications. The dilution with pig manure, instead of water, leads to a slightly better efficiency in the classical configuration. For the TPAD process, the trend is very similar, but the AHPD biogas plant indicates a reverse tendency. Overall, the recommendation from this article is to use the AHPD concept if the composition of the biogas is the most important. In the case in which the performance is the most important factor, it is favorable to use the TPAD configuration.

scholarly journals Effects of equal channel angular pressing and heat treatments on the microstructures and mechanical properties of selective laser melted and cast AlSi10Mg alloys

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Przemysław Snopiński ◽  
Mariusz Król ◽  
Marek Pagáč ◽  
Jana Petrů ◽  
Jiří Hajnyš ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Equal Channel Angular Pressing ◽  
Heat Treatments ◽  
Electron Backscattered Diffraction ◽  
Angular Pressing ◽  
Low Temperature Annealing ◽  
Transmission Electron ◽  
Before And After ◽  
The Impact

AbstractThis study investigated the impact of the equal channel angular pressing (ECAP) combined with heat treatments on the microstructure and mechanical properties of AlSi10Mg alloys fabricated via selective laser melting (SLM) and gravity casting. Special attention was directed towards determining the effect of post-fabrication heat treatments on the microstructural evolution of AlSi10Mg alloy fabricated using two different routes. Three initial alloy conditions were considered prior to ECAP deformation: (1) as-cast in solution treated (T4) condition, (2) SLM in T4 condition, (3) SLM subjected to low-temperature annealing. Light microscopy, transmission electron microscopy, X-ray diffraction line broadening analysis, and electron backscattered diffraction analysis were used to characterize the microstructures before and after ECAP. The results indicated that SLM followed by low-temperature annealing led to superior mechanical properties, relative to the two other conditions. Microscopic analyses revealed that the partial-cellular structure contributed to strong work hardening. This behavior enhanced the material’s strength because of the enhanced accumulation of geometrically necessary dislocations during ECAP deformation.

scholarly journals Transport Properties of Natural and Artificial Smart Fabrics Impregnated by Graphite Nanomaterial Stacks

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1018
Author(s):  
Carola Esposito Corcione ◽  
Francesca Ferrari ◽  
Raffaella Striani ◽  
Antonio Greco
Keyword(s):  
Electrical Conductivity ◽  
Transport Properties ◽  
Low Cost ◽  
Empirical Relationship ◽  
Theoretical Models ◽  
Expandable Graphite ◽  
Easy Method ◽  
Textile Materials ◽  
Fabric Materials ◽  
The Impact

In this work, we studied the transport properties (thermal and electrical conductivity) of smart fabric materials treated with graphite nanomaterial stacks–acetone suspensions. An innovative and easy method to produce graphite nanomaterial stacks–acetone-based formulations, starting from a low-cost expandable graphite, is proposed. An original, economical, fast, and easy method to increase the thermal and electrical conductivity of textile materials was also employed for the first time. The proposed method allows the impregnation of smart fabric materials, avoiding pre-coating of the fibers, thus reducing costs and processing time, while obtaining a great increase in the transport properties. Two kinds of textiles, cotton and Lycra®, were selected as they represent the most used natural and artificial fabrics, respectively. The impact of the dimensions of the produced graphite nanomaterial stacks–acetone-based suspensions on both the uniformity of the treatment and the transport properties of the selected textile materials was accurately evaluated using several experimental techniques. An empirical relationship between the two transport properties was also successfully identified. Finally, several theoretical models were applied to predict the transport properties of the developed smart fabric materials, evidencing a good agreement with the experimental data.

The Impact of the Business Environment on the Formalization of Informal Firms. The Case of Kosovo

Südosteuropa ◽  
2020 ◽  
Vol 68 (4) ◽  
pp. 505-529
Author(s):  
Kujtim Zylfijaj ◽  
Dimitar Nikoloski ◽  
Nadine Tournois
Keyword(s):  
Negative Impact ◽  
Positive Impact ◽  
Business Environment ◽  
Positive Influence ◽  
Policy Implications ◽  
Tax Reforms ◽  
Firm Level ◽  
Characteristics Analysis ◽  
Significant Negative Impact ◽  
The Impact

AbstractThe research presented here investigates the impact of the business environment on the formalization of informal firms, using firm-level data for 243 informal firms in Kosovo. The findings indicate that business-environment variables such as limited access to financing, the cost of financing, the unavailability of subsidies, tax rates, and corruption have a significant negative impact on the formalization of informal firms. In addition, firm-level characteristics analysis suggests that the age of the firm also exercises a significant negative impact, whereas sales volume exerts a significant positive impact on the formalization of informal firms. These findings have important policy implications and suggest that the abolition of barriers preventing access to financing, as well as tax reforms and a consistent struggle against corruption may have a positive influence on the formalization of informal firms. On the other hand, firm owners should consider formalization to be a means to help them have greater opportunities for survival and growth.

scholarly journals Electrically Conductive Networks from Hybrids of Carbon Nanotubes and Graphene Created by Laser Radiation

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1875
Author(s):  
Alexander Yu. Gerasimenko ◽  
Artem V. Kuksin ◽  
Yury P. Shaman ◽  
Evgeny P. Kitsyuk ◽  
Yulia O. Fedorova ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Laser Irradiation ◽  
Flexible Electronics ◽  
Threshold Energy ◽  
Wavelength Region ◽  
Hybrid Nanostructures ◽  
Graphene Sheets ◽  
Electrically Conductive ◽  
Walled Carbon Nanotubes

A technology for the formation of electrically conductive nanostructures from single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), and their hybrids with reduced graphene oxide (rGO) on Si substrate has been developed. Under the action of single pulses of laser irradiation, nanowelding of SWCNT and MWCNT nanotubes with graphene sheets was obtained. Dependences of electromagnetic wave absorption by films of short and long nanotubes with subnanometer and nanometer diameters on wavelength are calculated. It was determined from dependences that absorption maxima of various types of nanotubes are in the wavelength region of about 266 nm. It was found that contact between nanotube and graphene was formed in time up to 400 fs. Formation of networks of SWCNT/MWCNT and their hybrids with rGO at threshold energy densities of 0.3/0.5 J/cm2 is shown. With an increase in energy density above the threshold value, formation of amorphous carbon nanoinclusions on the surface of nanotubes was demonstrated. For all films, except the MWCNT film, an increase in defectiveness after laser irradiation was obtained, which is associated with appearance of C–C bonds with neighboring nanotubes or graphene sheets. CNTs played the role of bridges connecting graphene sheets. Laser-synthesized hybrid nanostructures demonstrated the highest hardness compared to pure nanotubes. Maximum hardness (52.7 GPa) was obtained for MWCNT/rGO topology. Regularity of an increase in electrical conductivity of nanostructures after laser irradiation has been established for films made of all nanomaterials. Hybrid structures of nanotubes and graphene sheets have the highest electrical conductivity compared to networks of pure nanotubes. Maximum electrical conductivity was obtained for MWCNT/rGO hybrid structure (~22.6 kS/m). Networks of nanotubes and CNT/rGO hybrids can be used to form strong electrically conductive interconnections in nanoelectronics, as well as to create components for flexible electronics and bioelectronics, including intelligent wearable devices (IWDs).

scholarly journals Midwives’ experiences of implementing respectful maternity care knowledge in daily maternity care practices after participating in a four-day RMC training

BMC Nursing ◽  
2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Veronica Millicent Dzomeku ◽  
Adwoa Bemah Boamah Mensah ◽  
Emmanuel Kweku Nakua ◽  
Pascal Agbadi ◽  
Jody R. Lori ◽  
...  
Keyword(s):  
Maternity Care ◽  
Positive Impact ◽  
Good Practice ◽  
Healthcare Facility ◽  
Positive Influence ◽  
Respectful Maternity Care ◽  
Training Workshop ◽  
Care Practices ◽  
The Impact ◽  
Childbearing Women

Abstract Background In Ghana, studies documenting the effectiveness of evidence-based specialized training programs to promote respectful maternity care (RMC) practices in healthcare facilities are few. Thus, we designed a four-day RMC training workshop and piloted it with selected midwives of a tertiary healthcare facility in Kumasi, Ghana. The present paper evaluated the impact of the training by exploring midwives’ experiences of implementing RMC knowledge in their daily maternity care practices 4 months after the training workshop. Methods Through a descriptive qualitative research design, we followed-up and conducted 14 in-depth interviews with participants of the RMC training, exploring their experiences of applying the acquired RMC knowledge in their daily maternity care practices. Data were managed and analysed using NVivo 12. Codes were collapsed into subthemes and assigned to three major predetermined themes. Results The findings have been broadly categorized into three themes: experiences of practising RMC in daily maternity care, health facility barriers to practising RMC, and recommendations for improving RMC practices. The midwives mentioned that applying the newly acquired RMC knowledge has positively improved their relationship with childbearing women, assisted them to effectively communicate with the women, and position them to recognize the autonomy of childbearing women. Despite the positive influence of the training on clinical practice, the midwives said the policy and the built environment in the hospital does not support the exploration of alternative birthing positions. Also, the hospital lacked the required logistics to ensure privacy for multiple childbearing women in the open labour ward. The midwives recommended that logistics for alternative birthing positions and privacy in the ward should be provided. Also, all midwives and staff of the hospital should be taken through the RMC training program to encourage good practice. Conclusion Despite the report of some RMC implementation challenges, the midwives noted that the 4-day RMC training has had a positive impact on their maternity caregiving practice in the hospital. Policies and programs aimed at addressing the issue of disrespect and abusive practices during maternity care should advocate and include the building of facilities that support alternative birthing positions and privacy of childbearing women during childbirth.

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