4,283 research outputs found
The Perception on Food Quality among Urban People
Contaminated and unhygienic food intake is a major problem in the urban cities of Bangladesh. This raises a serious concern for health of the urban citizens. The research investigates into the attitude of the urban educated people on their awareness of food safety. The findings of the study suggest a high degree of awareness amongst respondents of the attitudinal survey. People with higher educational background show higher degree of awareness of how the quality of food should be maintained. A lack of confidence on the functions of government regulatory agency in testing the food standard is also reflected in the study.
Design of Multi-Layered Lenses for Resolusion Enhancement
Lenses are important optical device having numerous applications in our day-to-day life. As the conventional lenses, we use concave or convex lenses. These lenses are made with natural materials and the image quality imperfect. Furthermore, they are bulky, and design is complex. Consequently, mass production is difficult.
The shapes of entrance and exit faces of lenses has impact on its imaging capability. The Lens material also play a vital role for reconstructing the image. Flat lenses can be considered as a good alternative of the conventional lenses. One of the advantages of this Flat lenses is that it can restore both the propagating and evanescent waves in the image plane. The conventional lenses only restore the information contained by the propagating waves and the evanescent waves that contains small subwavelength information of the object decays in the image plane. Flat Lenses are preferable in terms of image quality
Understanding soil water repellency under native vegetation in Australia: An empirical and molecular dynamics approach
Soil water repellency (SWR) is a major land management issue across southern Australia and inhibits the infiltration of water into soil with effects on the germination of crops and pastures and run-off in agricultural and forested land. SWR is a natural phenomenon and generally occurs in the surface layers of sandy soils where hydrophobic materials mostly of plant origin occur as particulate organic matter and as waxy coatings on soil particles. Although its incidence and severity have been anecdotally related to the previous native vegetation little is known about the specific organic compounds that may derive from this vegetation. Previous studies have concentrated on characterizing the contribution of soil organic matter, and this and the fact that soils are complex mixtures of a broad range of organic components may have obscured the contribution of a small concentration of compounds from the native species to SWR. Moreover, the precise distribution of these compounds (e.g., as coatings or in interstices between soil particles) and their contribution to SWR has not been quantified.
Although analysis of soil solvent extracts can identify the relative amounts of individual compounds, it is often difficult to determine the relative importance of all components in inducing SWR. It is even harder to determine synergistic effects from combinations of components. Experimental studies provide a broad understanding of the bulk effects of hydrophobic molecular coatings but do not provide a molecular level understanding of the coating structure or of its kinetic and/or thermodynamic stability. The molecular arrangement of those organic compounds on the soil particles have been shown to have implications for both the incidence and dynamics of SWR. Thus the present study employed a range of approches to understand SWR in native vegetation: i) quantifying the contribution of canopy derived exudates from native tree species to SWR, ii) discerning the contribution of organic matter in different pools (e.g., on particle surfaces, as interstitial matter) to SWR and iii) examining the physical interaction of the organic molecules (without and with water) with soil mineral surfaces.
Canopy derived exudates were captured using an improvised technique, and organic compounds were extracted using nonpolar and polar solvents. In order to discern the contribution of different carbon pools to SWR, soils were separated into mineral and interstitial matter. Soils were extracted using a sonication technique. Individual and combinations of compounds were loaded onto acid washed sand (AWS) using a rotary evaporator. This experimental loading and measurement was complemented by fully atomistic molecular dynamics simulations with Materials Studio v 7.0 to understand the physical interaction of the molecules with mineral surfaces.
A range of different organic compounds that are widely reported in the incidence of SWR were detected in the canopy derived exudates and soil extracts. They were mostly long-chain alkanes, fatty acids, phytols, phytanols, amides, aldehydes, ketones, terpenoids, steroids, and some complex ring containing structures. Though there was similarity in the composition of both the nonpolar and polar compounds of exudates of Banksia menziesii, Eucalyptus marginata, Xanthorrhoea preissii and Allocasuarina fraseriana, the concentration level of the chemical species was found to be significantly different. The concentrations were found to differ over the sampling period. For example, docosanoic acid was found to be dominant in the summer for B. menziesii and X. preissii. while in E. marginata and A. fraseriana it was evident in the winter.
Moreover, the concentration level of the chemical species derived from the soil extracts were also found to be significantly different between the species of A. fraseriana, E. marginata, E. wandoo and B. menziesii. Notably, the main difference between A. fraseriana and the other three species (E. marginata, E. wandoo and B. menziesii) was the presence of long chain fatty acids and fatty alcohols. The concentration of the compounds was even different in different soil components (e.g., minerals and interstitial matter) of the soil matrix. For example, the concentration level of the individual compound derived from the bulk soil was similar to the total concentration level of the compound derived from both the coarse mineral materials and interstitial matters.
The molecular level arrangement of various hydrophobic molecules with mineral surfaces also varied. For example, amphiphilic molecules at surface density of 2.3 molecs/nm2 were found in a tilted arrangement on kaolinite while on quartz surfaces they formed layered arrangements. However, silica did not favor a certain order of arrangement of the molecules due to its amorphous surface. The surface characteristics and polarity (abundance of OH groups) of the substrate (kaolinite > silica) were found to significantly modify the organo-mineral interactions. Different biogenic volatile organic compounds (BVOCs) or terpenoids commonly observed in vegetation smoke or forest fire, were not found to induce SWR. Moreover, the long chain amphiphilic molecules exhibited a balance between molecule-molecule and molecule-surface interactions on the quartz surface that supported surface adhesion, which in turn led to the formation of a hydrophobic layer. Furthermore, soil moisture or the addition of water molecules was found to significantly modify the conformation of molecules at the organo-mineral interfaces. For example, the polar kaolinite and silica surfaces were found to easily wet-up and reorganization of amphiphilic molecules on the surfaces took place following aquation. The stronger interaction between water and organic molecules can thus be inversely correlated to organo-mineral interaction on soil particles
Construction Workers\u27 Health and Safety During Post Disaster Reconstruction Phase: A Case Study in Nepal
The understanding of the concept of construction workersâ health and safety during the post-disaster reconstruction (PDR) phase is still unexplored. The objective of this study is to identify a knowledge gap in the literature through systematic literature review and to find out factors that affect the health and safety of the workers during PDR. To achieve the objectives, in-depth semi-structured interviews are conducted with different stakeholders such as Owners, General Contractors, Government Officials, Safety Supervisors, Engineers and Construction Workers in the context of Nepal Earthquake 2015. Interviews are conducted in a way that the respondents represent a wide range of perspectives. The findings of this study pointed out factors such as debris management, the participation of community people, using unskilled workers, immigrant workers as some of the factors which play a vital role from the safety aspect. Finally, the findings of this study introduce workersâ health and safety as an important issue in PDR planning. It will potentially help the authorities to integrate it in disaster preparedness and recovery planning
Role of non-timber forest products in sustaining forest-based livelihoods and rural households' resilience capacity in and around protected area- a Bangladesh study
People in developing world derive a significant part of their livelihoods
from various forest products, particularly non-timber forest products. This
article attempts to explore the contribution of NTFPs in sustaining
forest-based rural livelihood in and around a protected area of Bangladesh, and
their potential role in enhancing households resilience capacity. Based on
empirical investigation our study revealed that, local communities gather a
substantial amount of NTFPs from national park despite the official
restrictions. 27 percent households of the area received at least some cash
benefit from the collection, processing and selling of NTFPs, and NTFPs
contribute as HHs primary, supplementary and emergency sources of income. NTFPs
also constituted an estimated 19 percent of HHs net annual income, and were the
primary occupation for about 18 percent of the HHs. HHs dependency on nearby
forests for various NTFPs varied vis-a-vis their socio-economic condition as
well as with their location from the park. Based on our case study the article
also offers some clues for improving the situation in PA.Comment: To appear in Journal of Environmental Planning and Management, 201
Public sector reforms, privatisation and regimes of control in a Chinese enterprise
The Chinese economic reform has recently become a major focus of attention around the world. The underlying rationale for the Chinese government's privatisation and public sector reforms is the view that reformed state enterprises and privately managed firms will demonstrate superior management control and better performance, and hence encourage economic growth and employment. There are very few intensive case studies published in English journals studying whether firms privatised in China have reversed previous losses and introduced better management controls, leading to increased investment, productivity, and overall organizational effectiveness and efficiency. The researchers do not seek to deny the control problems of Chinese SOEs, but question the consequences of the new controls installed during the post-privatisation period. The paper also reveals a declining tendency in employment; altered distributions of wealth ? especially to the state ? and labour, and a lack of improvements in the accountability of privatised companies. Overall, the paper argues, the aims of reform policies in China, including better control, increased profitability and an improved working life for Chinese people, have not materialized. The paper calls for more research on the above issues in the Chinese context
Activation cross sections of -particle induced nuclear reactions on hafnium and deuteron induced nuclear reaction on tantalum: production of W/Ta generator
In the frame of a systematic study of charged particle production routes of
medically relevant radionuclei, the excitation function for indirect production
of Ta through Hf(,xn)W-Ta nuclear
reaction was measured for the first time up to 40 MeV. In parallel, the side
reactions Hf(,x)W,
Ta, Hf were also assessed.
Stacked foil irradiation technique and -ray spectrometry were used. New
experimental cross section data for the Ta(d,xn)W reaction are
also reported up to 40 MeV. The measured excitation functions are compared with
the results of the ALICE-IPPE, and EMPIRE nuclear reaction model codes and with
the TALYS 1.4 based data in the TENDL-2013 library. The thick target yields
were deduced and compared with yields of other charged particle ((p,4n), (d,5n)
and (He,x)) production routes for W
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