Recycling and the Environment: a Comparative Review Between Mineral-based Plastics and Bioplastics

Since their conception in the 1950s, mineral-based plastics have completely revolutionised our society with production reaching record highs year upon year. This cheap, and durable material has seen usage across a plethora of diverse industries and products, replacing traditional materials such as metals and wood. However, our reliance on mineral-based plastics has led to their improper disposal across the global, affecting our environments and ecosystems. As a response, different methods have been developed to help dispose of the large amounts of plastic waste produced, such as incineration or dumping in landfill sites, but these methods are not without their drawbacks including release of toxic substances into the air and leachate into the soil and waters respectively. Consequently, much interest is generated and channelled in recent years to the introduction of several types of biopolymers. These include plastics based on cellulosic esters, starch derivatives, polyhydroxybutyrate and polylactic acid. These biopolymers have been viewed as a suitable replacement for mineral-based plastics, and their production a good strategy towards sustainable development as they are mainly composed of biocompounds such as starch, cellulose and sugars. This short review article provides an overview as to whether biopolymers can rival mineral-based plastics considering properties such as mechanical strength, Young’s modulus and crystallinity and could they be regarded as a suitable material to reduce our reliance on mineral-based plastics, whilst simultaneously reducing non-renewable energy consumption and carbon dioxide emissions

Plastics and Environment: Is There a Happy Medium?

In 2013 alone, 56 million tons of Poly(ethylene terephthalate) (PET) was produced worldwide. It’s low cost of production, coupled with desirable properties such as high durability and plasticity has led to its extensive use in many different applications, from mobile phones to medical equipment to clothing. Demand for PET is steadily increasing year by year. However, PET is mineral-based and is a non-degradable material due to its synthetic nature. It accumulates within the environment globally, and this has led to collective global efforts for developing strategies to tackle the issue using various different options. Biopolymers such as Polyhydroxyalkanoate (PHA) present themselves as a possible solution and as suitable alternative to help manage the ever-rising global demand for plastics as well as alleviating the global environmental crisis arising from non-degradable plastics. Capable to be produced in an eco-friendly manner and possessing biodegradable properties, biopolymers should be set to replace non-degradable plastics, but despite extensive research on production of biodegradable plastics, the cost of their production is too high to lend them to large-scale production. This project focuses on economic production of PHAs. In this context, several approaches are adopted. Cheaper media such as orange peel, wheat bran, and spirulina with other quality enhancing ingredients have been tried; dual polymer production has been proved a possible option, and stage-wise fermentations, appart from fed-batch have been tried. Furthermore, downstream processing strategies such as planned time of harvest have the potential to attenuate adverse effects of extraction methods for PHA extraction. A holistic approach promises positive future for biopolymer industry

SV-wave with external force in saturated medium

There are past researches done for SV-wave with the absence of external force. This work aims to investigate the influence of external force in the propagation of SV-wave in the soluble and insoluble mediums. Isotropic wave model is derived for SV-wave with various forces in accordance to Duhamel Principle and their analytical solutions are used to compare with each other’s’ amplitudes. With the existence of high density fluid, diffusive waves with larger external force will induce higher amplitude. However, SV-waves are non-diffusive in low density medium and hence, this work concludes that wave diffusion by external force is subjected to the properties of the targeted medium

Effectiveness of microwave technique in early detection of breast abnormalities

In this paper, a breast phantom of CIRS Model 010A contains various known masses and sizes is studied. A measurement of S11 signals is taken at few locations on a breast surface using an open-ended coaxial probe. The obtained signals permit the extraction of the dielectric property of the masses. The result has shown that the smallest size detected through this probe is approximately 0.20 mm, small enough to be detected at early stage breast abnormality growth. This method undoubtedly recognizes the presence and location of possible abnormalities such as benign and malignant tissues. Although the model does not contain malignant tissues, this study demonstrates the viability of detecting small breast tumors using this approach. Index Terms - Breast abnormalities, dielectric properties, microwave technique, open-ended coaxial probe

Changes in particulate matter concentrations at different altitudinal levels with environmental dynamics

Ambient air quality is defined not only by the source strength but a variety of meteorological parameters as well. In the current study, ambient concentrations of PM along with temperature and relative humidity levels were monitored at seven different locations of Pakistan. A DustTrak DRX (Model 8533, TSI Inc.) was employed for twenty four hours real time monitoring of particulate matter at the selected sites. A considerable variation was observed in the 24 hour trend of particulate matter (PM) at different locations owing to variation in meteorological conditions due to different altitudes and seasons, and natural and anthropogenic sources in the vicinity. The highest average concentrations of PM2.5 (407μg/m3 were observed at highest elevation (Makra Peak, Shogran, 3089 m) while lowest averages (102 μg/m3) were obtained at the seaside (Hawks Bay, Karachi, 0 m).On the other hand PMTotal fraction exhibited highest levels at site B (506 μg/m3) and lowest at Site A (121 μg/m3).Correlation factors were determined for PM and meteorological parameters at each location. More research needs to be conducted to have a comprehensive knowledge about the physical parameters controlling particulate dispersal at different altitudes within the country

Changes in particulate matter concentrations at different altitudinal levels with environmental dynamics

Ambient air quality is defined not only by the source strength but a variety of meteorological parameters as well. In the current study, ambient concentrations of PM along with temperature and relative humidity levels were monitored at seven different locations of Pakistan. A DustTrak DRX (Model 8533, TSI Inc.) was employed for twenty four hours real time monitoring of particulate matter at the selected sites. A considerable variation was observed in the 24 hour trend of particulate matter (PM) at different locations owing to variation in meteorological conditions due to different altitudes and seasons, and natural and anthropogenic sources in the vicinity. The highest average concentrations of PM2.5 (407 mu g/m(3)) were observed at highest elevation (Makra Peak, Shogran, 3089 m) while lowest averages (102 mu g/m(3)) were obtained at the seaside (Hawks Bay, Karachi, 0 m). On the other hand PMTotal fraction exhibited highest levels at site B (506 mu g/m(3)) and lowest at Site A (121 mu g/m(3)). Correlation factors were determined for PM and meteorological parameters at each location. More research needs to be conducted to have a comprehensive knowledge about the physical parameters controlling particulate dispersal at different altitudes within the country

A Study of the PDGF Signaling Pathway with PRISM

In this paper, we apply the probabilistic model checker PRISM to the analysis of a biological system -- the Platelet-Derived Growth Factor (PDGF) signaling pathway, demonstrating in detail how this pathway can be analyzed in PRISM. We show that quantitative verification can yield a better understanding of the PDGF signaling pathway.Comment: In Proceedings CompMod 2011, arXiv:1109.104

Chemical constituents and bioactivity of piper sarmentosum: A mini review

Herbs with medicinal potential are important for health and wellness. The main aim of this review article was to disseminate important information regarding the use of Piper sarmentosum as natural medicine. P. sarmentosum have been reported to possess a varying degree of hypoglycemic, antidiabetic and other additional properties. The antioxidant properties of the herbs may be effective in controlling the oxidative damage. The review article highlights the positive role of traditional herbs as alternative medicine

Population dynamics of mantis shrimp, Harpiosquilla harpax in the coastal waters of Pantai Remis, Perak, Peninsular Malaysia

This study estimated the length-weight relationship, sex ratio and population parameters of mantis shrimp, Harpiosquilla harpax from the coastal waters of Pantai Remis, Perak, Malaysia between February 2012 and October 2012. Total length and weight of 804 specimens of H. harpax were measured and the sex ratio was 1: 0.83 (M: F). Males of H. harpax were dominant over the females throughout the study period. The value of relative growth coefficient (b) for H. harpax was 2.698 for males and 2.884 for females. For the length-weight relationship, the species exhibited negative allometric growth for males, females and combined sexes. The L∞ and K of H. harpax was 18.38 cm and 1.10 yr-1 for males and 21.53 cm and 0.75 yr-1 for females. The growth performance index (φ') was calculated as 2.57 for males and 2.54 for females. Total mortality (Z), natural mortality and fishing mortality was found to be 4.084 yr-1, 2.247 yr-1 and 1.837 yr-1 for males whereas 3.259 yr-1, 1.674 yr-1, 1.585 yr-1 for females, respectively. The recruitment pattern of the species was continuous throughout the year for males and females. The exploitation level (E) of H. harpax was estimated at 0.449 for males and 0.486 for females. It is revealed that the stock of H. harpax was very close to optimum level of exploitation (E = 0.50) in the coastal waters of Pantai Remis, Perak, Malaysia

Citrulline as a Diagnostic Parameter and a Major Amino Acid Constituent of Cerebrospinal Fluid in Hepatic Coma

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