Finite element modeling and experimental proof of NEMS-based silicon pillar resonators for nanoparticle mass sensing applications

The potential use of nanoelectromechanical systems (NEMS) created in silicon nanopillars (SiNPLs) is investigated in this work as a new generation of aerosol nanoparticle (NP)-detecting device. The sensor structures are created and simulated using a finite element modeling (FEM) tool of COMSOL Multiphysics 4.3b to study the resonant characteristics and the sensitivity of the SiNPL for femtogram NP mass detection in 3-D structures. The SiNPL arrays use a piezoelectric stack for resonance excitation. To achieve an optimal structure and to investigate the etching effect on the fabricated resonators, SiNPLs with different designs of meshes, sidewall profiles, heights, and diameters are simulated and analyzed. To validate the FEM results, fabricated SiNPLs with a high aspect ratio of approximately 60 are used and characterized in resonant frequency measurements where their results agree well with those simulated by FEM. Furthermore, the deflection of a SiNPL can be enhanced by increasing the applied piezoactuator voltage. By depositing different NPs [i.e., gold (Au), silver (Ag), titanium dioxide (TiO₂), silicon dioxide (SiO₂), and carbon black NPs] on the SiNPLs, the decrease of the resonant frequency is clearly shown confirming their potential to be used as airborne NP mass sensor with femtogram resolution level. A coupling concept of the SiNPL arrays with piezoresistive cantilever resonator in terms of the mass loading effect is also studied concerning the possibility of obtaining electrical readout signal from the resonant sensors.     

Collaborative Learning based on Convolutional Features and Correlation Filter for Visual Tracking

International Journal of Control, Automation and Systems - One of the most important and challenging research topics in the area of computer vision is visual object tracking, which is relevant to...     

Independent Retailer Restocking Choices in Urban Goods Movement and Interaction Effects with Traditional Markets

Traditional markets play a key role in local supply chains in many countries, often influencing retailer decisions due to their inherent attractiveness. In contrast to restocking choices for retailers as part of large chains, choices of independent retailers driven by local traditional markets have not been widely researched and are not well understood. This paper analyses the factors influencing independent retailer restocking choices and investigates the interplay between the presence of traditional markets and retailer choices. Bandung city in Indonesia is chosen for the study where independent retailers are prevalent, and where a number of traditional markets are thriving. A retrospective questionnaire was used to capture independent retailer restocking behaviour and generation models were calibrated to arrive at the trip propensity. Discrete choice models were estimated to explain the retailer preferences for supplier location and transport service choice. Results indicate that trips generated by independent retailers are explained by the presence of traditional markets and retailers’ vehicle ownership, in addition to the standard variables such as number of persons employed, weekly goods demand and average shipment weight. As for restocking location choice, retailers are more likely to choose suppliers within a traditional market where the number of wholesaler units is larger. Furthermore, the choice of traditional markets has a positive influence on whether retailers choose to use their own vehicle to restock their shops.

     

Cellulose acetate–silica fume membrane: characterization and application for separation of starch and maltose

Maltose is one of the starch derivatives. Maltose can be produced by starch hydrolysis using any kind of hydrolytic process. One of the methods to separate a mixture of both compounds is using porous membrane. In this research, a novel type of hybrid membrane was prepared from a mixture of cellulose acetate and silica fume. Silica fume is widely used in the domain of construction as cement material, whereas in this research silica fume was successfully used as membrane material. Various compositions of membrane dope solutions were prepared for obtaining the membranes used for separation of starch and maltose. Such synthesized membranes demonstrate a good performance in separation processes. The best performance is achieved when the composition of cellulose acetate in membrane dope solution is 15 % (w/w) in N,N-dimethylacetamide solvent and the mass ratio between cellulose acetate and silica fume is 4:1. For this composition, the rejection of membranes towards starch and maltose is 87 and 2 %, respectively, at working pressure of 3 bar and compaction time of 2 h. Infrared spectrum indicates no new peaks are found compared to raw materials’ spectral peaks. Thus, it can be concluded that the interaction between the cellulose acetate and silica fume is merely a physical type. From the observation of cross-sectional SEM images, we can remark that the morphology of such a membrane is porous. X-ray diffractogram indicates that the synthesized membranes are amorphous.     

Physician assessment of patient smoking in Indonesia: a public health priority

Objective

To explore Indonesian physician''s smoking behaviours, their attitudes and clinical practices towards smoking cessation.

Design

Cross‐sectional survey.

Setting

Physicians working in Jogjakarta Province, Indonesia, between October and December 2003.

Subjects

447 of 690 (65%) physicians with clinical responsibilities responded to the survey (236 men, 211 women), of which 15% were medical faculty, 35% residents and 50% community physicians.

Results

22% of male (n = 50) and 1% of female (n = 2) physicians were current smokers. Approximately 72% of physicians did not routinely ask about their patient''s smoking status. A majority of physicians (80%) believed that smoking up to 10 cigarettes a day was not harmful for health. The predictors for asking patients about smoking were being male, a non‐smoker and a medical resident. The odds of advising patients to quit were significantly greater among physicians who perceived themselves as sufficiently trained in smoking cessation.

Conclusions

Lack of training in smoking cessation seems to be a major obstacle to physicians actively engaging in smoking cessation activities. Indonesian physicians need to be educated on the importance of routinely asking their patients about their tobacco use and offering practical advice on how to quit smoking.Tobacco use is one of the greatest causes of preventable deaths and disease in human history. According to the World Bank, four‐fifths of the world''s 1.1 billion smokers live in low‐income or middle‐income countries.¹ East Asian and Pacific countries currently account for about 38% of the world''s smokers and men, especially those aged 30–49 years, account for about 80% of these smokers.² In Indonesia, 59% of male, but only <5% of women, smoke.³ Notably, the rates of tobacco use, especially among adolescents and young adults in East Asia, continue to rise.¹ Although reliable national data are unavailable for Indonesia, estimates in 2004 showed a high incidence rate of tobacco‐attributable mortality and morbidity.⁴ For example, in 2002, the International Agency of Research on Cancer Globocan estimated that the age‐standardised mortality of respiratory tract cancer in Indonesia among men was 68.5 per 100 000 population, but that among women was only 21.5 per 100 000 population.⁵Nations such as Indonesia continue to bear significant health and socioeconomic burdens associated with tobacco use, primarily due to aggressive tobacco industries marketing and the slow progress in tobacco control activities resulting from a strong dependency of the national economy on the tobacco trade.⁶ To reduce the economic and health burden from cigarette smoking, effective measures for smoking cessation and tobacco control are clearly needed. Public health education, and governmental policies such as taxation on sales and restrictions on advertisement may serve as useful tools to limit the use of tobacco products.^7,8 Currently, such measures are lacking in Indonesia.Smoking behaviour and attitudes towards smoking cessation by healthcare providers in Western countries have been studied extensively.^9,10,11 Research findings suggest that asking about smoking and offering advice about cessation help smokers quit.^{12,13,14,15,16} Of equal importance is the observation that the smoking status of healthcare providers may influence their willingness to offer smoking cessation advice to smokers.^16,17 Unfortunately, limited research is available on non‐Western countries in regard to behaviours, perceptions and attitudes towards smoking among physicians and other healthcare providers.^16,18,19,20Understanding the attitudes of health professionals towards cessation of tobacco use is an important early step in the development of a country''s comprehensive anti‐tobacco initiative. This step is especially important in countries like Indonesia, where there are few anti‐tobacco initiatives and physicians play a particularly important role as opinion leaders and role models. To understand physician''s attitudes towards tobacco, we conducted a survey of physicians to explore a range of issues including smoking behaviours, and their attitudes and clinical practices regarding smoking.     

Position coordinate representation of flying arrow and analysis of its performance indicator

In the arrow manufacturing business, the distribution of impact points on a target after a repetitive shooting test is an important element in assessing arrow performance. The impact points of the arrows shown on shooting paper serve as crucial indicators when determining arrow performance. However, shooting paper lacks accuracy and requires regular replacement, and the digitization of the relationship among the impact points is a difficult task. Advanced research studies currently focus on the external factors of arrow performance and arrows in-flight vibration, but such studies have neglected to investigate the distribution of impact points because of insufficient methods of assessing arrow performance and intuitive numerical data. In this paper, we propose a system that can convert the position of a flying arrow into coordinates and an algorithm that expresses the arrow position coordinates. The precision of arrow position coordinate measurement system is improved from an initial error of 2.46 mm to 0.452 mm after the correction. In addition, we suggest an indicator for the objective assessment of arrow performance using the coordinates from the arrow position coordinate measuring system. By analyzing the arrow performance of multiple arrows and arrow types, it is possible to select the optimal arrow and arrow model for a designated bow installed on the launcher.     

Optimization of pretreatment of Jatropha oil with high free fatty acids for biodiesel production

A central composite rotatable design and response surface methodology were used in order to investigate the individual and combined effects of the ethanol-to-oil ratio, H₂SO₄ concentration, temperature and time of reaction on the reduction of free fatty acid (FFA) in jatropha oil. A quadratic polynomial model relating the reaction variables with FFA reduction was developed, presenting a good coefficient of determination (R²= 0.893). For reducing FFA to less than 1%, the optimal combination was found to be 0.62 v·v^-1 ethanol-to-oil ratio (14.9 v·v^-1 ethanol-to-FFA ratio), 1.7% v·v^-1 H₂SO₄ concentration, and 79 min reaction time at a reaction temperature of 54°C. These results are of great relevance to maximize methyl esters formation by transesterification using an alkaline catalyst.