Size Reduction Method Research Articles

Physical and Thermal Properties of <i>Zingiber officinale</i> Rosc. (Ginger) Rhizome Fine Particle as a Function of Grinding System

In this study,Zingiber officinale(ginger) rhizome fine particles were prepared by using food processor, hammer mill and planetary ball mill and tested for their physical and thermal properties. The physical changes by means of particle size, surface morphology, FT-IR and thermal stability (TGA) were investigated. The size reduction method had a distinct effect on physical and thermal properties of ginger rhizome tested. Average particle size of ginger rhizome after using food processor and hammer mill was around 50µm and 20µm respectively while after using planetary ball mill the ginger rhizome was successfully reduced to nanoscale (222.3 nm). Higher degree of granule surface fractured was observed as a result of a planetary ball milling process based on FESEM images. There were also some notable differences of FT-IR spectra detected. By comparing the spectra, the stretching vibration peak of OH at 3292 cm-1[U1]and the symmetric stretching vibration peak of the NO2and C=C at 1369 – 1639.51cm-1 for ginger rhizome ground using food processor were disappeared. Yet, presence of possibly strong alkenes group (in the range 2850 – 2970cm-1) were observed in all samples tested. Ginger rhizome particles obtained from hammer milling process were found to be more stable to thermal effect where the decomposed temperature was 276.64°C as compared to samples milling using food processor and planetary ball mill. These results would provide useful insight for exploring the potential applications of ginger rhizome fine powder as functional food ingredient as well as in pharmaceutical applications. [U1]Check typing of superscript.

Fabrication of Silicon Nanowires by Electron Beam Lithography and Thermal Oxidation Size Reduction Method

A simple method for the fabrication of silicon nanowires using Electron Beam Lithography (EBL) combined with thermal oxidation size reduction method is presented. EBL is used to define the initial silicon nanowires of dimensions approximately 100 nm. Size-reduction method is employed for reaching true nanoscale of dimensions approximately 20 nm. Dry oxidation of silicon is well investigated process for self-limited size-reduction of silicon nanowires. In this paper, successful size reduction of silicon nanowires is presented and surface topography characterizations using Atomic Force Microscopy (AFM) are reported.

Size Reduction of Series‐Fed Two Dipole Array Antenna Using Top‐Loaded Elements

ABSTRACTIn this article, a method for size reduction of a series‐fed two dipole array (STDA) antenna using top‐loaded elements is presented. In order to reduce the lateral size of a conventional STDA antenna, rectangular patch‐shaped top loading is used for the two dipole elements of the STDA antenna and a grooved ground plane is used by adding a patch at both ends of the ground plane. The effects of varying the length and width of the rectangular patch‐shaped top loading on the antenna performances, such as the input reflection coefficient and the realized gain, are investigated. A proposed size‐reduced STDA antenna covering a frequency band ranging from 1.7 GHz to 2.7 GHz with a gain > 5 dBi is designed and fabricated on an FR4 substrate. The total width of the fabricated prototype of the proposed antenna is reduced by approximately 14.3% compared to the conventional STDA antenna, and it presents a 48.7% bandwidth in the range of 1.68–2.76 GHz and a stable gain of 5.6–6.0 dBi with minimal degradation. Moreover, a front‐to‐back ratio is improved by about 0.7–4.8 dB. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2288–2293, 2013

A novel high-pressure precipitation tandem homogenization technology for drug nanocrystals production – a case study with ursodeoxycholic acid

To overcome the limitations of the conventional particle size reduction technologies, a novel combinative particle size reduction method for the effective production of homogeneous nanosuspensions was investigated. Ursodeoxycholic acid, a poorly soluble drug representative, was tried to prepare nanosuspension by homogenization technology and high-pressure precipitation tandem homogenization technology. It was shown that the combinative approach could significantly improve the particle size reduction effectiveness over conventional homogenization approach. The Box–Behnken design analysis for process optimization revealed that the acceptable UDCA-NS was obtained wherein the optimal values of A, B, C and D were 10%, 500 bar, 0.125 and 600 bar, respectively. SEM results demonstrated that no significant aggregation or crystals growth could be observed in the freeze-dried UDCA nanocrystals. The DSC and XRD results showed that UDCA remained in a crystalline state. Dissolution velocities of the freeze-dried UDCA-NS powder were distinctly superior compared to those of the crude powder and physical mixture. The high-pressure precipitation tandem homogenization technology can be a good choice for nanosuspension preparation of poorly soluble UDCA, due to high efficiency of particle size reduction.

Effect of four different size reduction methods on the particle size, solubility enhancement and physical stability of nicergoline nanocrystals

Nicergoline, a poorly soluble active pharmaceutical ingredient, possesses vaso-active properties which causes peripheral and central vasodilatation. In this study, nanocrystals of nicergoline were prepared in an aqueous solution of polysorbate 80 (nanosuspension) by using four different laboratory scale size reduction techniques: high pressure homogenization (HPH), bead milling (BM) and combination techniques (high pressure homogenization followed by bead milling HPH + BM, and bead milling followed by high pressure homogenization BM + HPH). Nanocrystals were investigated regarding to their mean particles size, zeta potential and particle dissolution. A short term physical stability study on nanocrystals stored at three different temperatures (4, 20 and 40 °C) was performed to evaluate the tendency to change in particle size, aggregation and zeta potential. The size reduction technique and the process parameters like milling time, number of homogenization cycles and pressure greatly affected the size of nanocrystals. Among the techniques used, the combination techniques showed superior and consistent particle size reduction compared to the other two methods, HPH + BM and BM + HPH giving nanocrystals of a mean particle size of 260 and 353 nm, respectively. The particle dissolution was increased for any nanocrystals samples, but it was particularly increased by HPH and combination techniques. Independently to the production method, nicergoline nanocrystals showed slight increase in particle size over the time, but remained below 500 nm at 20 °C and refrigeration conditions.

공통 DGS를 이용한 발진기의 소형화 설계

본 논문에서는 공통 결함접지구조(common defected ground structure, CDGS)를 이용하여 설계한 초고주파 발진기에 대하여 기술한다. 먼저 일반적인 스터브 공진기를 사용하여 발진기를 설계하고, 이를 종래처럼 DGS를 삽입하여 소형화하는 방법을 이용하였다. 최종적으로 DGS 공진기 부분을 반으로 접은 공통 DGS 구조를 이용하여 크기를 대폭 줄인 발진기를 설계하였다. 종래의 DGS를 이용한 경우보다 더욱 소형화된 회로를 얻기 위하여 공통 DGS 구조를 삽입하였다. 공통 DGS 구조를 이용하기 위하여 접혀진 신호선로는 3차원적인 신호선 비어홀(signal via-hole)로 서로 연결된다. 한 설계예로 2.1GHz대에서 소신호 트랜지스터와 공통 DGS 구조를 이용하여 소형화한 발진기를 설계하였다. 설계한 발진기는 표준형 회로에 비하여 11mm만큼 감소한 크기를 가졌다. 제작한 회로를 실제로 측정한 결과 6.7dBm의 출력과 -133dBc/Hz@1MHz의 위상잡음 특성을 얻었다. 출력의 크기는 소형화 이전과 유사한데, 이로써 제안한 발진기 구조의 타당성이 검증된다. In this paper, a design of size-reduced microwave oscillator using common defected ground structure (common DGS) is described. At first, an oscillator is designed using the normal stub resonator, and the conventional DGS patterns are inserted for the first trial of size-reduction. Finally, the DGS resonator section is folded by half size in order to adopt the common DGS, and this produces the proposed size-reduced oscillator. Common DGS pattern is inserted for a better size-reduction than when conventional DGSs are used. The folded transmission line is connected using the 3-dimensional signal via-holes. For an example of design, a 2.1GHz oscillator is designed and fabricated using a small signal transistor and common DGS, which shows the size-reduction of 11 mm. The measurement shows 6.7dBm of output power and -133dBc/Hz@1MHz of phase noise. The measured performances are so similar to those of the oscillators before size-reduction and prove the proposed size-reduction method of oscillators using common DGS.

A micro compact coplanar power divider at X-band with finite-width ground plane based on GaAs MMIC technology

A micro coplanar Wilkinson power divider at X-band on GaAs substrate is presented in this paper. The proposed power divider introduces a size reduction method, and the length of the transmission line is reduced to λ/8 (at 10 GHz). Since the two segments of the two edge coupled quarter-wave asymmetric coplanar striplines (ACPSs) with finite-width ground plane are closed to each other, their characteristic parameters, such as characteristic impedance and attenuation coefficient, are obtained using the quasi-static conformal mapping technique (CMT) of coupled coplanar waveguide (CCPW) with finite-width ground plane. S-parameters for the power divider are deduced in the case of quasi-static TEM even–odd mode. The fabrication process is compatible with the GaAs MMIC process. The measured S-parameters are compared with the simulated results of HFSS v.11 and the calculated results of TEM even–odd analysis. Simulated results show that it has reflection loss less of 16.5 dB and insertion loss less of 3.6 dB. Measured results show that the divider has reflection loss less of 15.0 dB and insertion loss less of 3.5 dB. Compared with conventional Wilkinson power divider, the length of the power divider is shortened from 2,620 to 1,570 μm.

Size Reduction of Cellulosic Biomass in Biofuel Manufacturing: Separating the Confounding Effects of Particle Size and Biomass Crystallinity

Increasing demands and concerns for reliable supply of liquid transportation fuels make it important to find alternative sources to petroleum-based fuels. Cellulosic biofuels provide one such alternative in the short to medium term. Size reduction is the first step for converting biomass into biofuels. In the literature, there are inconsistent reports about the effects of particle size and biomass crystallinity on sugar yield (proportional to biofuel yield). An important reason for this inconsistence is that particle formation in current size reduction methods is not well controlled, causing the effects of these two variables confounded. One paper investigating the confounding effects of particle size and biomass crystallinity using a metal-cutting (milling) process was previously published in this journal. This paper presents a follow-up study. In this study, a lathe was used to produce poplar wood particles with the same crystallinity but different sizes, making it possible to study the effects of particle size on biofuel yield independently without being confounded by the effects of biomass crystallinity. Results showed that, for the three levels of particle size used in this study, sugar yield increased as particle size became smaller. This study also revealed future research opportunities to understand the effects of size reduction and biomass crystallinity in cellulosic biofuel manufacturing.

BruteSuppression: a size reduction method for Apriori rule sets

Association rule mining can provide genuine insight into the data being analysed; however, rule sets can be extremely large, and therefore difficult and time-consuming for the user to interpret. We propose reducing the size of Apriori rule sets by removing overlapping rules, and compare this approach with two standard methods for reducing rule set size: increasing the minimum confidence parameter, and increasing the minimum antecedent support parameter. We evaluate the rule sets in terms of confidence and coverage, as well as two rule interestingness measures that favour rules with antecedent conditions that are poor individual predictors of the target class, as we assume that these represent potentially interesting rules. We also examine the distribution of the rules graphically, to assess whether particular classes of rules are eliminated. We show that removing overlapping rules substantially reduces rule set size in most cases, and alters the character of a rule set less than if the standard parameters are used to constrain the rule set to the same size. Based on our results, we aim to extend the Apriori algorithm to incorporate the suppression of overlapping rules.

Milling of magnesium powders without additives

Abstract Mechanical milling of ductile metals and alloys into fine powders is difficult to achieve due to particle agglomeration. Even though cryogenic milling and/or wet milling can lead to substantial reduction of particle size, the production of fine powders from ductile metals and alloys is a difficult process. The current study deals with the milling of Mg and examines alternative processing methods that would yield an efficient size reduction. Two methods were studied; milling with MgH 2 addition, and milling the powders pre-deformed by equal channel angular pressing (ECAP). The study showed that both methods are successful in preventing particle agglomeration resulting in a significant reduction in particle size. Equal channel angular pressing has the advantage that could be applied to all metals and alloys whereas milling with hydride could only be applied to metals forming their own hydride. It is concluded that, of the two methods, milling with hydride addition is a more effective method of size reduction.

Influence of different pre-treatment routes on the anaerobic digestion of a filamentous algae

The anaerobic digestion of outdoor cultivated Rhizoclonium biomass was investigated in this study. The influence of applying mechanical and biological pre-treatment methods prior to the biomass digestion on the overall methane yields was examined. The results show that the application of a combined biomass blending (<0.1 mm length) and an enzymatic pre-treatment improved the methane yields by >20% compared to use of a mechanical size reduction method alone. The methane yields from Rhizoclonium biomass were however observed to be considerably lower than those of other algae species from the literature.

Small Patch Antennas Incorporated With a Substrate Integrated Irregular Ground

This paper presents a novel method for size reduction of patch antennas by introducing an irregular ground structure to provide capacitive and inductive loading to the patch. Each of the four corners of the square patch is assigned with a pair of metallic walls. These special metallic walls located underneath the patch are constructed and integrated within the microwave substrate by connected vias. The vertical portion of the walls introduces the inductance whereas the separation between the two parallel walls creates the capacitance. Additional capacitances are also created between the flat strips connecting the vias and the radiating patch. No modifications are made to the square patch. With the presence of the substrate integrated irregular ground (SIIG) structure, the antenna finds a significant size reduction by the capacitive and inductive loading effect. For the proposed linearly-polarized antenna operating at 2.635 GHz, we achieve a total patch area reduction of 75.6% experimentally when compared with a half-wavelength patch antenna loaded with the same substrate. Furthermore, by using two sets of connecting strips with different lengths, two orthogonal modes are excited for circular polarization and similar size reduction effect is achieved.

Leaching of indium from obsolete liquid crystal displays: Comparing grinding with electrical disintegration in context of LCA

In order to develop an effective recycling system for obsolete Liquid Crystal Displays (LCDs), which would enable both the leaching of indium (In) and the recovery of a pure glass fraction for recycling, an effective liberation or size-reduction method would be an important pre-treatment step. Therefore, in this study, two different types of liberation methods: (1) conventional grinding, and (2) electrical disintegration have been tested and evaluated in the context of Life Cycle Assessment (LCA). In other words, the above-mentioned methods were compared in order to find out the one that ensures the highest leaching capacity for indium, as well as the lowest environmental burden. One of the main findings of this study was that the electrical disintegration was the most effective liberation method, since it fully liberated the indium containing-layer, ensuring a leaching capacity of 968.5mg-In/kg-LCD. In turn, the estimate for the environmental burden was approximately five times smaller when compared with the conventional grinding.

선박 통신용 HF 휩 안테나의 소형화

본 논문에서는 선박 통신용 HF 휩 안테나의 소형화 방법을 제안한다. HF 휩 안테나의 크기를 줄이기 위해 선형 휩 안테나의 끝 부분을 헬리컬 형태로 변형하였다. 상용 휩 안테나에 비해 60% 정도의 크기를 갖는 휩 안테나를 설계하였고, 상용의 휩 안테나와 변형된 휩 안테나를 사용한 통신실험을 수행하였다. 실험을 통해 제안하는 휩 안테나가 선박 통신용 상용 휩 안테나를 대체할 수 있음을 확인하였다. In this paper, we present the size reduction method of HF whip antenna for ship communication. To reduce the size of the HF whip, the end part of linear whip is modified to helical type. We designed the whip antenna with 60% size of the commercial whip antenna and carried out communication experiments using the commercial and the designed whip antennas. From the experimental results, we found that the proposed whip antenna can replace the commercial whip antenna for ship communication.

Size Reduction of Cellulosic Biomass in Biofuel Manufacturing: A Study on Confounding Effects of Particle Size and Biomass Crystallinity

Biofuels derived from cellulosic biomass offer an alternative to petroleum-based liquid transportation fuels. In order to convert cellulosic biomass into biofuels, size reduction is a necessary step along with pretreatment, enzymatic hydrolysis, and fermentation. In the literature, there are inconsistent reports about why size reduction affects sugar yield (proportional to biofuel yield). An important reason for the inconsistence is that particle formation in current size reduction methods is not well controlled, causing effects of some biomass structural parameters confounded. In this study, a metal-cutting (milling) process is used for size reduction of poplar wood, where particle formation can be well controlled to prevent the effects of multiple parameters from being confounded. The results of this study provide explanations for some inconsistent reports in the literature. These results also reveal some opportunities for future research to understand the effects of size reduction on cellulosic biofuel manufacturing.

Characterization of Meander Dipole Antennas With a Geometry-Based, Frequency-Independent Lumped Element Model

Meander antennas have gained widespread use in applications such as radio frequency identification (RFID) devices where space for the antenna is limited or a low-frequency operation is required. Several size-reduction and synthesis methods have been proposed over time. However, few studies have focused on developing models to characterize the operation of meander antennas. In addition, existing models are frequency-dependent, which means that they are inherently narrowband. An alternative model that is based entirely on the geometry of a meander dipole antenna (MDA) and is frequency-independent is proposed. To enhance the accuracy of the proposed model, the effect of mutual capacitances introduced through bending of the antenna wire is incorporated. The mutual capacitances are also a function of the antenna geometry. This model is expected to be more broadband relative to existing models. The equivalent circuit model proposed is validated through comparison to numerical simulations in EMCoS, a moment-method-based software package. The discrepancies between predictions of the resonant frequencies of MDAs with our model and simulation results are found to be less than 3%. Two classes of meander dipole antennas are introduced.

Laser Fragmentation as an Efficient Size-Reduction Method for Pulmonary Drug Discovery: Proof-of-Concept Study of Beclomethasone Dipropionate

Femtoand nanosecond lasers were used to produce micron-sized particles of beclomethasone dipropionate (BDP) in water. These novel processes were compared with traditional milling methods in terms of particle size, degradation and physicochemical properties. Results showed that similarly to conventional milling methods, minimal chemical degradation and amorphization were induced by the laser processes. As laser micronization requires minimal amounts of drug, this process is well suited for the discovery of pulmonary drugs.

Effects of pretreatment methods on health-related functional properties of high dietary fibre powder from lime residues

Epidemiological studies have revealed that consumption of dietary fibre (DF) leads to many health benefits. Lime residues, which are by-products obtained after juice extraction, were used as raw material to produce DF powder. The residues are high in DF and possess a good balance between insoluble dietary fibre (IDF) and soluble dietary fibre (SDF). To process lime residues into value added products, some treatments prior to drying are required to reduce the bitterness, and this may affect the functional and nutritional properties of DF powder. This study investigated the effects of pretreatment methods of blanching, blanching-ethanol soaking (95% v/v for 30min) and particle size reduction (38–450μm) on selected health related functional and nutritional properties of DF from lime residues. The lime residues were dried at 60°C before grinding. The functional and nutritional properties of interest included glucose adsorption capacity (GAC), glucose retardation index (GRI) and bile acid retardation index (BRI). The results show that DF powder prepared either by blanching or blanching followed by ethanol soaking prior to drying exhibited higher GRI and BRI. The pretreatments, however, did not affect the GAC. DF powder with smaller sizes also possessed higher GRI and BRI. The DF product with particle size in the range of 38–63μm, and pretreated by blanching and ethanol soaking exhibited the highest GRI and BRI among all samples studied.

Engineering TCP transmission and retransmission mechanisms for wireless networks

Transmission Control Protocol (TCP) provides mechanisms for reliable data communications. Although it works well in wired networks, it fails to offer satisfactory performance in lossy and wireless environments. And in the multi-hop wireless infrastructure, packet delivery suffers high cumulative loss rate if traveling over multiple wireless hops. The Selective acknowledgment (SACK) is one header option that might be used to combat segment corruptions in air channels. In this paper, an alternative set of flow control mechanisms is proposed to handle high packet loss rate in a wireless medium. Using a measurement-based mechanism, sustainable segment delivery is achievable through a novel size-reduction method. Multiple segment retransmission mechanisms are introduced to reduce successive timeout events. One single byte loss is sufficient to waste all other bytes in a file received at a destination. That is, a good TCP flow control mechanism should provide a high successful file transmission completion rate, and this is set as our design goal. Through thorough simulations, our proposed multi-segment retransmission designs perform with higher successful file transfer rate and fewer timeout events than NewReno and SACK under a wide range of packet loss probabilities.

A memory size reduction method of pipelined IFFT processor for OFDM systems

In this paper, we propose a new IFFT design method for orthogonal frequency division multiplexing (OFDM) systems to reduce the memory size of IFFT based on a combined integer mapping of three IFFT input signals: modulated data, pilot and null signals. The proposed method focuses on reducing the size of memory cells in the first two stages of the pipelined architectures since the first two stages require 75% of the total memory cells. By simulations of 2048-point IFFT design for cognitive radio systems, it is shown that the proposed IFFT design method achieves more than about 35% reduction in gate count and about 34% reduction in power consumption compared with conventional IFFT design.