scholarly journals The Synthesis of Peculiar Structure of Springlike Multiwall Carbon Nanofibers/Nanotubes via Mechanothermal Method

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Sahebali Manafi ◽  
Mohammad Reza Rahimipour ◽  
Iman Mobasherpour ◽  
Atefeh Soltanmoradi
Keyword(s):  
Carbon Nanofibers ◽  
Large Scale ◽  
Annealing Temperature ◽  
Milling Time ◽  
Nanocomposite Materials ◽  
Scale Production ◽  
Multiwalled Carbon ◽  
Large Scale Production ◽  
First Time ◽  
Multiwall Carbon

Mechanothermal (MT) method is one of the methods used for large-scale production of carbon nanotubes/nanofibers. The different peculiar morphologies of carbon allotropes are introduced with an extraordinary structure for the first time by MT method. In this paper, the influence of milling time and annealing temperature on the crystallinity and morphology of the synthesized nanopowders was investigated. Surprisingly, in this investigation, we report the synthesis of springlike multiwalled carbon nanofibers (S-MWCNFs) by a two-step annealing of milled graphite in an Ar atmosphere. On the other hand, the MT method could be used for the preparation of suitable structures with applications in nanocomposite materials, which is an important task in the era of nanotechnology.

Are the Pre-Diffusion Phases Shortening?

2010 ◽  
pp. 36-52
Author(s):  
J. R. Ortt
Keyword(s):  
Research And Development ◽  
Large Scale ◽  
High Tech ◽  
Scale Production ◽  
Large Scale Production ◽  
First Time ◽  
And Diffusion ◽  
Over Time

This chapter focuses on the pre-diffusion phases for high-tech products. These phases last from the first time a technology is mastered and demonstrated up to the start of the large-scale production and diffusion of products based on that technology. The purpose of this chapter is to underline the managerial relevance of the pre-diffusion phases. Two questions will be answered in particular: (1) How long do these pre-diffusion phases last for high-tech products? (2) Have these phases shortened or not over the last 150 years? Fifty-three cases of high-tech products, invented between 1837 and 1998, are investigated. The pre-diffusion phases are shown to last 16 years on average, but their length varies considerably per case. No proof for the shortening of these phases over time is found. The resources devoted to research and development in different fields of expertise may have increased but the length of the pre-diffusion phases has not shortened accordingly.

The Scalability of Wet Ball Milling for The Production of Nanosuspensions

2019 ◽  
Vol 7 (2) ◽  
pp. 147-161 ◽  
Author(s):  
Maria L.A.D. Lestari ◽  
Rainer H. Müller ◽  
Jan P. Möschwitzer
Keyword(s):  
Ball Milling ◽  
Large Scale ◽  
Milling Time ◽  
High Energy ◽  
Small Scale ◽  
Particle Sizes ◽  
Scale Production ◽  
Batch Mode ◽  
Pharmaceutical Ingredients ◽  
Large Scale Production

Background: Miniaturization of nanosuspensions preparation is a necessity in order to enable proper formulation screening before nanosizing can be performed on a large scale. Ideally, the information generated at small scale is predictive for large scale production. Objective: This study was aimed to investigate the scalability when producing nanosuspensions starting from a 10 g scale of nanosuspension using low energy wet ball milling up to production scales of 120 g nanosuspension and 2 kg nanosuspension by using a standard high energy wet ball milling operated in batch mode or recirculation mode, respectively. Methods: Two different active pharmaceutical ingredients, i.e. curcumin and hesperetin, have been used in this study. The investigated factors include the milling time, milling speed, and the type of mill. Results: Comparable particle sizes of about 151 nm to 190 nm were obtained for both active pharmaceutical ingredients at the same milling time and milling speed when the drugs were processed at 10 g using low energy wet ball milling or 120 g using high energy wet ball milling in batch mode, respectively. However, an adjustment of the milling speed was needed for the 2 kg scale produced using high energy wet ball milling in recirculation mode to obtain particle sizes comparable to the small scale process. Conclusion: These results confirm in general, the scalability of wet ball milling as well as the suitability of small scale processing in order to correctly identify the most suitable formulations for large scale production using high energy milling.

scholarly journals Novel Green Synthesis of Graphene Layers using Zante Currants and Graphene Oxide

2018 ◽  
Vol 34 (6) ◽  
pp. 2832-2837 ◽  
Author(s):  
Mohd Zaid Ansari ◽  
Mohammad Nadeem Lone ◽  
Shabana Sajid ◽  
Weqar Ahmad Siddiqui
Keyword(s):  
Graphene Oxide ◽  
Large Scale ◽  
Uv Spectrophotometry ◽  
Scale Production ◽  
Graphene Layers ◽  
Large Scale Production ◽  
Reduced Graphene ◽  
Reduction Effect ◽  
First Time ◽  
Facile Route

The present work shows a facile route for the preparation of graphene layers and for the first time Zante currants extract used for the effective deoxygenation of graphene oxide has been reported. Zante currants (ZC) extract reduce effectively GO into few layered structures of graphene (FLG). The morphology of few layers graphene and graphene oxide (GO) were investigated by SEM and TEM. Reduction effect on graphene oxide confirm by other technique like Raman, FTIR, XRD and UV spectrophotometry. This procedure keep away the use of hazardous chemicals, thus providing a new hope for large scale production of chemically reduced graphene.

PROPAGATION AND PRODUCTION OF GAC (MOMORDICA COCHINCHINENSIS SPRENG.), A GREENHOUSE CASE STUDY

2012 ◽  
Vol 49 (2) ◽  
pp. 234-243 ◽  
Author(s):  
SOPHIE E. PARKS ◽  
CARLY T. MURRAY ◽  
DAVID L. GALE ◽  
BASEM AL-KHAWALDEH ◽  
LORRAINE J. SPOHR
Keyword(s):  
Large Scale ◽  
Scale Production ◽  
Large Scale Production ◽  
Momordica Cochinchinensis ◽  
Increasing Demand ◽  
Potential Methods ◽  
Enhancing Production ◽  
First Time ◽  
Male To Female

SUMMARYGreater cultivation of the underutilised Gac fruit, Momordica cochinchinensis, by poorly resourced householders and farmers would potentially improve livelihoods, and, on a larger scale, meet the increasing demand for Gac as a health product. Cultivation methods need to be developed to suit small- and large-scale production and must consider the unpredictable ratio of male to female plants grown from seed, and slow growth induced by cool temperatures. In this study, we examined the responses of Gac to propagation and protected cropping techniques to identify potential methods for increasing production. Plants germinated from seed in seed-raising mix under warm and humid conditions were grown hydroponically to maturity in a climate-controlled greenhouse during a temperate winter, producing fruits that were harvested ripe, from 44 weeks after sowing. Cuttings taken from female plants were dipped in indole-3-butyric rooting hormone powder or gel, or were left untreated, and then placed in rock wool, potting mix, water or closed media sachet. All treatment combinations, with the exception of the untreated potting mix, permitted the development of healthy plants in a second greenhouse crop. Growing plants from seed, then vegetatively increasing the number of productive female plants by cuttings is a means to increase Gac production with limited resources. Gac production using greenhouse technology, as described here for the first time, is relevant to other temperate regions. The finding that larger fruits have a higher percentage of edible aril than smaller fruits provides a new area of investigation towards enhancing production.

scholarly journals Mitigating Quantization Lobes in mmWave Low-bit Reconfigurable Reflective Surfaces

2020 ◽  
Author(s):  
Panagiotis Theofanopoulos ◽  
Bharath Kashyap ◽  
Yiran Cui ◽  
Georgios Trichopoulos
Keyword(s):  
Large Scale ◽  
Optical Measurement ◽  
Random Phase ◽  
Single Layer ◽  
Scale Production ◽  
Low Loss ◽  
Large Scale Production ◽  
First Time ◽  
Phase Randomization ◽  
Reflective Surfaces

We present a method for the mitigation of quantization lobes in single-bit reconfigurable reflective surfaces (RRSs). Typically, RRSs are planar beamforming structures consisting of hundreds or thousands of antennas with integrated tunable switches. Under plane-wave illumination, single-bit RRSs suffer from undesired side lobes or quantization lobes, which are caused by the periodicity of the errors due to the limited number of bits used in phase quantization. In this work, we present a topology that suppresses the quantization lobes using single-layer, 1-bit RRSs, by implementing a fixed but random phase delay in every unit-cell. The introduction of phase randomization breaks the periodicity of the quantization errors, thus reducing the quantization lobe level (QLL). We carry out a theoretical analysis to demonstrate the effect of phase randomization in RRSs, and for the first time, provide the condition for choosing the range of randomization required to achieve the lowest sidelobe level (SLL). Leveraging this condition, we design a single-layer, 1-bit 30×30 randomized RRS at 222.5 GHz. The reflective surface is fabricated on a thin, low-loss alumina ribbon ceramic wafer from Corning Inc. using a simplified fabrication technique suitable for large-scale production of mmWave/THz RRSs. Finally, we present the radar cross-section (RCS) characterization results obtained from a quasi-optical measurement setup validating the mitigation of quantization lobes using the proposed randomization technique.

Industrial Synthesis of Whisker Carbon Nanotubes

2016 ◽  
Vol 852 ◽  
pp. 514-519 ◽  
Author(s):  
Xiao Gang Sun ◽  
Zhi Wen Qiu ◽  
Long Chen ◽  
Man Yuan Cai ◽  
Zhi Peng Pang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Large Scale ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Scale Production ◽  
Multiwalled Carbon ◽  
Large Scale Production ◽  
New Type

Since the first observation of carbon nanotubes (CNTs) in 1991, their synthesis techniques has been extensively investigated. The chemical vapor deposition (CVD) process have attracted much attention because of both their versatility and easy large scale production for CNTs . This paper is focused on a catalytic CVD-based method for synthesis of whisker multiwalled carbon nanotubes (WMWCNTs). The new type of carbon nanotube is similar to the whisker. The morphology of the WMWCNTs are very different from traditional carbon nanotubes prepared by traditional chemical vapor deposition process. The traditional CNTs were twisted and entangled with each other. These suggested that there are a lot of deficiencies on the CNTs and are difficult to disperse in matrix materials. The as-produced WMWCNTs are very straight and not entangled with each other. The line structure means that WMWCNTs are easily dispersed in matrix materials than traditional CNTs which are twined together. The crystallinity of WMWCNTs increased to 96% which was much higher than traditional CNTs after graphitization treatment at 2800°C.

scholarly journals A Facile Synthesis of (PIM-Polyimide)- (6FDA-Durene-Polyimide) Copolymer as Novel Polymer Membranes for CO2 Separation

2019 ◽  
Author(s):  
Iqubal Hossain ◽  
Abu Zafar Al Munsur ◽  
Tae-Hyun Kim
Keyword(s):  
Gas Separation ◽  
Large Scale ◽  
Thermomechanical Properties ◽  
Random Copolymers ◽  
Separation Performance ◽  
Scale Production ◽  
Large Scale Production ◽  
One Step ◽  
First Time ◽  
Gas Separation Performance

Random copolymers made of both (PIM-polyimide) and (6FDA-durene-PI) were prepared for the first time by a facile one-step polycondensation reaction. By combining the highly porous and contorted structure of PIM (polymers with intrinsic microporosity) and high thermomechanical properties of PI (polyimide), the membranes obtained from these random copolymers [(PIM-PI)x-(6FDA-durene-PI)y] showed high CO2 permeability (> 1047 Barrer) with moderate CO2/N2 (> 16.5) and CO2/CH4 (> 18) selectivity, together with excellent thermal and mechanical properties. The membranes prepared from three different compositions of two comonomers (1:4, 1:6 and 1:10 of x:y), all showed similar morphological and physical properties, and gas separation performance, indicating ease of synthesis and practicability for large-scale production. The gas separation performance of these membranes at various pressure ranges (100–1500 torr) was also investigated.

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