Open AccessArticle
Validation of a Miniaturized Spectrometer for Trace Detection of Explosives by Surface-Enhanced Raman Spectroscopy
Challenges 2016, 7(2), 14; doi:10.3390/challe7020014 -
Abstract
Surface-enhanced Raman spectroscopy (SERS) measurements of some common military explosives were performed with a table-top micro-Raman system integrated with a Serstech R785 miniaturized device, comprising a spectrometer and detector for near-infrared (NIR) laser excitation (785 nm). R785 was tested as the main [...] Read more.
Surface-enhanced Raman spectroscopy (SERS) measurements of some common military explosives were performed with a table-top micro-Raman system integrated with a Serstech R785 miniaturized device, comprising a spectrometer and detector for near-infrared (NIR) laser excitation (785 nm). R785 was tested as the main component of a miniaturized SERS detector, designed for in situ and stand-alone sensing of molecules released at low concentrations, as could happen in the case of traces of explosives found in an illegal bomb factory, where solid microparticles of explosives could be released in the air and then collected on the sensor’s surface, if placed near the factory, as a consequence of bomb preparation. SERS spectra were obtained, exciting samples in picogram quantities on specific substrates, starting from standard commercial solutions. The main vibrational features of each substance were clearly identified also in low quantities. The amount of the sampled substance was determined through the analysis of scanning electron microscope images, while the spectral resolution and the detector sensitivity were sufficiently high to clearly distinguish spectra belonging to different samples with an exposure time of 10 s. A principal component analysis procedure was applied to the experimental data to understand which are the main factors affecting spectra variation across different samples. The score plots for the first three principal components show that the examined explosive materials can be clearly classified on the basis of their SERS spectra. Full article
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Open AccessArticle
Potential for Reuse of E-Plastics through Processing by Compression Molding
Challenges 2016, 7(1), 13; doi:10.3390/challe7010013 -
Abstract
The amounts of e-waste, consisting of metal (e-metals) and plastic (e-plastics) streams from electronic goods, are increasing in the United States and elsewhere. The e-metals waste streams are being recycled to a reasonable degree due to the value of precious metals. E-plastic [...] Read more.
The amounts of e-waste, consisting of metal (e-metals) and plastic (e-plastics) streams from electronic goods, are increasing in the United States and elsewhere. The e-metals waste streams are being recycled to a reasonable degree due to the value of precious metals. E-plastic waste streams currently are not recycled or reused to a significant extent. As a result, most e-plastics are disposed of by landfilling or thermal treatment, or sent overseas for alleged recycling or reuse, any of which could result in unsafe worker exposure and release into the environment. Two of the major barriers to e-plastics’ reuse or recycling are the mixed plastic content and the presence in the e-plastics of flame retardants (FR), of which two classes in particular, the brominated flame retardants (BFR) and organo-phosphorus flame retardants (OPFR), have associated health concerns. The major goal of this project is to investigate the possibility of direct reuse of e-plastics in compression molding. Preliminary data generated have identified a molding procedure that yields remanufactured e-plastics having a tensile strength of 29.3 MPa. This moderate strength level is suspected to be due to inclusions of plastic bits that did not melt and internal voids from out-gassing. Handheld X-ray fluorescence (XRF) was utilized to characterize elemental components in the e-plastics tested for compression molding. Several high “hits” for Br were found that could not be predicted visually. The preliminary XRF data for BFR and OPFR in this work are helpful for environmental and occupational hazard assessments of compression molding activities. Additionally, methods are suggested to characterize the metals, BFR, and OPFR content of the e-plastics using several different additional laboratory analytical techniques to determine the suitability for cost-effective and easy-to-use technologies. Full article
Open AccessArticle
Tie-Up Cycles in Long-Term Mating. Part I: Theory
Challenges 2016, 7(1), 12; doi:10.3390/challe7010012 -
Abstract
In this paper, we propose a new approach to couple formation and dynamics that abridges findings from sexual strategies theory and attachment theory to develop a framework where the sexual and emotional aspects of mating are considered in their strategic interaction. Our [...] Read more.
In this paper, we propose a new approach to couple formation and dynamics that abridges findings from sexual strategies theory and attachment theory to develop a framework where the sexual and emotional aspects of mating are considered in their strategic interaction. Our approach presents several testable implications, some of which find interesting correspondences in the existing literature. Our main result is that, according to our approach, there are six typical dynamic interaction patterns that are more or less conducive to the formation of a stable couple, and that set out an interesting typology for the analysis of real (as well as fictional, as we will see in the second part of the paper) mating behaviors and dynamics. Full article
Open AccessOpinion
Alternative Energies and Fossil Fuels in the Bioeconomy Era: What is Needed in the Next Five Years for Real Change
Challenges 2016, 7(1), 11; doi:10.3390/challe7010011 -
Abstract Sustainable biomass feedstock is the key to sustainable biofuels.[...] Full article
Open AccessArticle
Modeling Autonomous Decision-Making on Energy and Environmental Management Using Petri-Net: The Case Study of a Community in Bandung, Indonesia
Challenges 2016, 7(1), 9; doi:10.3390/challe7010009 -
Abstract
Autonomous decision-making in this study is defined as the process where decision-makers have the freedom and ability to find problems, select goals, and make decisions for achieving the selected problems/goals by themselves. Autonomous behavior is considered significant for achieving decision implementation, especially [...] Read more.
Autonomous decision-making in this study is defined as the process where decision-makers have the freedom and ability to find problems, select goals, and make decisions for achieving the selected problems/goals by themselves. Autonomous behavior is considered significant for achieving decision implementation, especially in the context of energy and environmental management, where multiple stakeholders are involved and each stakeholder holds valuable local information for making decisions. This paper aims to build a structured process in modeling the autonomous decision-making. A practical decision-making process in waste-to-energy conversion activities in a community in Bandung, Indonesia, is selected as a case study. The decision-making process here is considered as a discrete event system, which is then represented as a Petri-net model. First, the decision-making process in the case study is decomposed into discrete events or decision-making stages, and the stakeholders’ properties in each stage are extracted from the case study. Second, several stakeholder properties that indicate autonomous behavior are identified as autonomous properties. Third, presented is a method to develop the decision-making process as a Petri-net model. The model is utilized for identifying the critical points for verifying the performance of the derived Petri-net. Full article
Open AccessOpinion
Flaws and Drawbacks in Present Regulation and the Need to Take Action and Support the Renewable Energies Policies in Italy
Challenges 2016, 7(1), 10; doi:10.3390/challe7010010 -
Abstract Renewable energies is an important sector that needs to be sustained and increased by the action of policies and economic support.[...] Full article
Open AccessLetter
Policies Supporting Renewable Energies Uses: The Next Big Challenge
Challenges 2016, 7(1), 8; doi:10.3390/challe7010008 -
Abstract
The question in the referendum on 17 April is: “At the end of the concessions presently authorized for extraction plants in the sea, at a distance within 12 km from the coast of Italy, are you in favor of stopping the extraction, [...] Read more.
The question in the referendum on 17 April is: “At the end of the concessions presently authorized for extraction plants in the sea, at a distance within 12 km from the coast of Italy, are you in favor of stopping the extraction, even if there is still some methane or oil to be extracted?”.[...] Full article
Open AccessOpinion
Fossil Fuels, Let’s Leave Them under Earth. Four Reasons to Vote “Yes” at the Italian Referendum on Drilling
Challenges 2016, 7(1), 7; doi:10.3390/challe7010007 -
Abstract
The referendum that will be held on 17 April 2016 is calling Italians to express their willingness on an aspect of licensing the sea drilling activities: The end of the licenses to the offshore exploitation of fossil fuel resources within the 12 [...] Read more.
The referendum that will be held on 17 April 2016 is calling Italians to express their willingness on an aspect of licensing the sea drilling activities: The end of the licenses to the offshore exploitation of fossil fuel resources within the 12 miles from the coast. Full article
Open AccessEditorial
On Energy Resources, Climate Change, Fossil Fuels, and Drilling. Challenges in Tackling Problems by Governments in Europe and USA
Challenges 2016, 7(1), 6; doi:10.3390/challe7010006 -
Abstract
This month in Italy a public consultation will decide (by majority, in case 50% of voters will participate) whether to renew the ongoing concessions between Italian government and drilling companies at the end of their contracts, even if the fossil fuels have [...] Read more.
This month in Italy a public consultation will decide (by majority, in case 50% of voters will participate) whether to renew the ongoing concessions between Italian government and drilling companies at the end of their contracts, even if the fossil fuels have not been extracted completely.[...] Full article
Open AccessArticle
Bridging the Gap between Eco-Design and the Human Thinking System
Challenges 2016, 7(1), 5; doi:10.3390/challe7010005 -
Abstract
Technological progress has enabled widespread adoption and use of consumer electronics, changing how global society lives and works. This progress has come with immense environmental cost, including extraction of scarce materials, consumption of fossil fuels, and growing e-waste challenges. Eco-design has emerged [...] Read more.
Technological progress has enabled widespread adoption and use of consumer electronics, changing how global society lives and works. This progress has come with immense environmental cost, including extraction of scarce materials, consumption of fossil fuels, and growing e-waste challenges. Eco-design has emerged as a promising approach to reduce the environmental footprint of electronics by integrating sustainability-oriented decisions early in the product realization process. However, most approaches focus on the product itself, not on the consumer who ultimately decides how to purchase, use, maintain, and dispose of the device. This article presents a new framework to guide designers in developing products with features that encourage consumers to use them in an environmentally sustainable manner. The Sustainable Behavior Design (SBD) framework links common design concepts (ergonomic, emotional, preventative, and interaction design) with core aspects of the human thinking system to create features to make users aware of their behavior and decisions (reflective thinking) or result in sustainable behaviors even when users are unaware (automatic thinking). The SBD framework is demonstrated using a case study on a smartphone, a high demand product. The reimagined smartphone design integrates solutions addressing both automatic and reflective thinking systems, potentially reducing life cycle impacts by almost 30%. Full article
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Open AccessArticle
Practical Eco-Design and Eco-Innovation of Consumer Electronics—the Case of Mobile Phones
Challenges 2016, 7(1), 3; doi:10.3390/challe7010003 -
Abstract
Annually, it is estimated that about 4 billion units of consumer electronics for mobile communications are produced worldwide. This could lead to various ecological imbalances unless the design and disposal of the products are handled optimally. To illustrate how industry looks at [...] Read more.
Annually, it is estimated that about 4 billion units of consumer electronics for mobile communications are produced worldwide. This could lead to various ecological imbalances unless the design and disposal of the products are handled optimally. To illustrate how industry looks at and responds to the increasing social awareness, this article describes how sustainability is successfully implemented in practice at a large Chinese company, developing and producing various kinds of electronic products used for communication. It also describes how a variety of eco-innovations and business models contribute to reducing the environmental impact; for example, through increased recovery and recycling. A new kind of eco-design procedure is presented along with a new methodology which shows how a mobile phone gradually becomes more sustainable from one generation to the next. The issues with and set-up of new eco-labeling schemes for mobile phones, eco-rating, is described in detail. The conclusion is that due to high competition between companies, the industry acts resourcefully and a lot is done to the save the ecological environment. Full article
Open AccessBrief Report
Use of Bacteriocinogenic Cultures without Inhibiting Cheese Associated Nonstarter Lactic Acid Bacteria; A Trial with Lactobacillus plantarum
Challenges 2016, 7(1), 4; doi:10.3390/challe7010004 -
Abstract
Bacteriocinogenic cultures can represent a natural way to increase the safety of cheeses made from raw milk, in which a relevant role in ripening and flavor formation is exerted by the nonstarter lactic acid bacteria (NSLAB). Since the latter can be inhibited [...] Read more.
Bacteriocinogenic cultures can represent a natural way to increase the safety of cheeses made from raw milk, in which a relevant role in ripening and flavor formation is exerted by the nonstarter lactic acid bacteria (NSLAB). Since the latter can be inhibited by bacteriocin producers, this study evaluated to which extent a nisinogenic culture inoculated at low initial levels can affect the growth rate and peptide degradation activity of the nisin-sensitive cheese isolate Lactobacillus plantarum LZ by comparison with its isogenic variant, L. plantarum LZNI, with increased immunity to nisin. A growth delay of the nisin sensitive strain was observed only when its initial number was 100-fold lower than the nisin producer and nisin was added as an inducer of its own production. In this case, the amount of free α-amino groups was significantly different between cultures of L. plantarum LZ and LZNI only at Day 1. Reverse Phase High Performance Liquid Chromatography (RP-HPLC) highlighted a few differences between the peptide profiles of co-cultures L. plantarum LZ and LZNI. However, results showed that the bacteriocin producer did not dramatically influence the behavior of the sensitive NSLAB and that the evaluation of the effects on microbial contaminants in cheese is worthwhile. Full article
Open AccessReview
Challenges in Creating Evidence in Environmental Health Risk Assessments: The Example of Second-Hand Smoke
Challenges 2016, 7(1), 2; doi:10.3390/challe7010002 -
Abstract
Public health interventions are directed to influence the (state of a) risk factor, either by behavioral or environmental changes. Therefore, environmental health risk assessments are highly relevant for public health decision making and policy development. The credibility of an environmental health risk [...] Read more.
Public health interventions are directed to influence the (state of a) risk factor, either by behavioral or environmental changes. Therefore, environmental health risk assessments are highly relevant for public health decision making and policy development. The credibility of an environmental health risk assessment depends, to a large extent, on the strength of the scientific evidence on which it is based. In this article, the main challenges for assessing the impact of a potential adverse health effect from an environmental pollutant are described. Second-hand smoke (SHS) was chosen to illustrate the current state of evidence. The assessment of the impact of potential adverse health effects from environmental risk factors is dependent on several issues, such as the hypothesized health outcome, the nature of the exposure, the dose-response-relationship and the variability and susceptibility of the exposed population. The example of SHS exposure highlights the need for evidence-based public health. Several challenges in terms of study design, assessment methods, as well as data analysis and synthesis with respect to the stratification of results, and consideration of bias and confounding exist. Future research needs to take into account which methods and techniques will be used to generate evidence for population-level decisions. Full article
Open AccessEditorial
Acknowledgement to Reviewers of Challenges in 2015
Challenges 2016, 7(1), 1; doi:10.3390/challe7010001 -
Abstract The editors of Challenges would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2015. [...] Full article
Open AccessReview
Wildfire Likelihood’s Elements: A Literature Review
Challenges 2015, 6(2), 282-293; doi:10.3390/challe6020282 -
Abstract
Wildfires occur in different climatic zones, forest cover types and eras. Wildfire or forest fire has always shaped the landscape. Different methodologies and indexes have emerged to determine the likelihood of wildfire, commonly confused with the wildfire hazard. However, none of these [...] Read more.
Wildfires occur in different climatic zones, forest cover types and eras. Wildfire or forest fire has always shaped the landscape. Different methodologies and indexes have emerged to determine the likelihood of wildfire, commonly confused with the wildfire hazard. However, none of these are universal or portable. In this paper, we have gone through several articles, projects and books. The aim was to identify factors related to the ignition of a wildfire. Consequently, 28 factors were presented and categorized into climatic, topographic, in-situ, historical and anthropogenic factors. It is the first step in building a generalized, acceptable and portable method to determine the wildfire risk. Its creation is strongly related to the prevention and better assessment of this phenomenon. Full article
Open AccessArticle
Estimation of Groundwater Recharges in Odeda Local Government Area, Ogun State, Nigeria using Empirical Formulae
Challenges 2015, 6(2), 271-281; doi:10.3390/challe6020271 -
Abstract
Estimation and forecast of groundwater recharge and capacities of aquifers are essential issues in water resource investigation. In the current research, groundwater recharge and the recharge coefficient were determined through a case study using empirical methods applicable to the tropical zones. The [...] Read more.
Estimation and forecast of groundwater recharge and capacities of aquifers are essential issues in water resource investigation. In the current research, groundwater recharge and the recharge coefficient were determined through a case study using empirical methods applicable to the tropical zones. The related climatological data between January 1983 and December 2014 were collected from Ogun-Oshun River Basin Development Authority (OORBDA), Ogun State, Nigeria. Using empirical formulae. The results showed that groundwater recharge was 194.7 mm per year, evapotranspiration was 1296.2 mm per year, and the recharge coefficient was 20.2% for the study area. The result also showed that about 11% of rainfall infiltrated the aquifer, 73% was lost to evapotranspiration, and 16% ended up as run-off. Correlation between climatic parameters and groundwater recharge showed the highest correlation between recharge and rainfall. Temperature, humidity, solar radiation and evapotranspiraton were obtained at the 0.01 significance level; the results of linear regressions proved that precipitation has a significant effect (with R2 = 0.983) on estimated recharge. Full article
Open AccessArticle
Wind Energy Based Electric Vehicle Charging Stations Sitting. A GIS/Wind Resource Assessment Approach
Challenges 2015, 6(2), 258-270; doi:10.3390/challe6020258 -
Abstract
The transportation sector is severely correlated with major problems in environment, citizens’ health, climate and economy. Issues such as traffic, fuel cost and parking space have make life more difficult, especially in the dense urban environment. Thus, there is a great need [...] Read more.
The transportation sector is severely correlated with major problems in environment, citizens’ health, climate and economy. Issues such as traffic, fuel cost and parking space have make life more difficult, especially in the dense urban environment. Thus, there is a great need for the development of the electric vehicle (EV) sector. The number of cars in cities has increased so much that the current transportation system (roads, parking places, traffic lights, etc.) cannot accommodate them properly. The increasing number of vehicles does not affect only humans but also the environment, through air and noise pollution. According to EPA, the 39.2% of total gas emissions in 2007 was caused by transportation activities. Studies have shown that the pollutants are not only gathered in the major roads and/or highways but can travel depending on the meteorological conditions leading to generic pollution. The promotion of EVs and the charging stations are both equally required to be further developed in order EVs to move out of the cities and finally confront the range problem. In this work, a wind resource and a GIS analysis optimizes in a wider area the sitting of wind based charging stations and proposes an optimizing methodology. Full article
Open AccessArticle
Human Health Impact of Natural and Artificial Radioactivity Levels in the Sediments and Fish of Bonny Estuary, Niger Delta, Nigeria
Challenges 2015, 6(2), 244-257; doi:10.3390/challe6020244 -
Abstract
There is widespread contamination of the environment of the Niger Delta, which may include enhanced background levels of naturally occurring radioactive materials (NORM) due to oil production and rapid urbanization activities. Sediments and seafood from the Bonny estuary, Niger Delta, were collected [...] Read more.
There is widespread contamination of the environment of the Niger Delta, which may include enhanced background levels of naturally occurring radioactive materials (NORM) due to oil production and rapid urbanization activities. Sediments and seafood from the Bonny estuary, Niger Delta, were collected for the purpose of determining baseline data on artificial and natural radioactivity and estimation of effective doses for the public due to ingestion of seafood from the study area. The highest and lowest activity concentrations were reported for 40K and 137Cs in both sediments and fish samples of the Bonny estuary. There was some evidence of spatial variability in the 40K and 137Cs data, with the latter being the likely result of dredging. Other radionuclides were not significantly different between sites impacted by industrial activities or not. Activity of radionuclides measured in the sediments of the study area were higher than reported elsewhere in the Niger Delta and Nigeria and higher than reported global averages by UNSCEAR. The total highest activity concentration in all fish species of gamma emitting radionuclides was observed for 40K, followed by 238U, 232Th and 226Ra, respectively, while 137Cs had the lowest activity concentration. However, 210Po activities were the most important in terms of dose contribution. Consumption of molluscs at typical rates could result in doses exceeding 1 mSv·y−1. Although this baseline data may not be conclusive on prevailing trends in radioactivity in the study area, higher consumption rates of the species studied may have public health consequences due to effects of low dose ionising radiation. Full article
Open AccessArticle
Childhood Diarrhea Determinants in Sub-Saharan Africa: A Cross Sectional Study of Tiko-Cameroon
Challenges 2015, 6(2), 229-243; doi:10.3390/challe6020229 -
Abstract
Introduction: Diarrhea remains the second leading cause of death among children under five years globally. Nearly one in five child deaths, about 1.5 million each year, are due to diarrhea. It kills more young children than Acquired Immunodeficiency Syndrome (AIDS), malaria [...] Read more.
Introduction: Diarrhea remains the second leading cause of death among children under five years globally. Nearly one in five child deaths, about 1.5 million each year, are due to diarrhea. It kills more young children than Acquired Immunodeficiency Syndrome (AIDS), malaria and measles combined. World Health Organization has accordingly underlined the need for epidemiological surveys of infantile diarrhea in all geographical areas. The main research objectives were to estimate the prevalence of diarrhea and identify factors associated with diarrheal diseases in Tiko city in Cameroon. Method: The present study was a cross-sectional community household survey which was conducted in Tiko town from 1st to 31st of August 2012. With the use of a questionnaire, a total of 602 households that had at least one child under five years of age were interviewed. Mothers/caregivers were questioned on the morbidity of diarrhea and the logistic regression model was employed to examine the determinants of childhood diarrhea. Both univariable and multivariable data analysis was performed using SPSS version 16.0. Results: The results of this study showed that the prevalence of diarrhea was 23.8% and children under 24 months were highly affected. We found children using the main toilet and other types of toilet facilities such as bushes, diaper, and streams (OR: 0.194; p < 0.001, 95% CI) and usage of narrow-mouth container for storage of drinking water (OR: 0.492; p < 0.001, 95% CI) less likely to suffer from diarrhea. In contrast, higher rates of diarrhea prevalence were seen in children from households with two or more siblings (OR: 1.222; p < 0.001, 95% CI) and whose mothers/caregivers never had the knowledge of safe sources of drinking water (OR: 1.849; p < 0.01, 95% CI). Conclusion: Childhood diarrhea is a public health problem in Tiko city. Hence, interventions aimed at reducing the prevalence should take into consideration the integration of family planning activities in the prevention of childhood diarrhea and the deployed of health personals to educate the community to adopt a hygienic behavior. Future research on the topic should be qualitative inquiry to complement the quantitative nature of this study. Full article
Open AccessArticle
Climate Action Gaming Experiment: Methods and Example Results
Challenges 2015, 6(2), 202-228; doi:10.3390/challe6020202 -
Abstract
An exercise has been prepared and executed to simulate international interactions on policies related to greenhouse gases and global albedo management. Simulation participants are each assigned one of six regions that together contain all of the countries in the world. Participants make [...] Read more.
An exercise has been prepared and executed to simulate international interactions on policies related to greenhouse gases and global albedo management. Simulation participants are each assigned one of six regions that together contain all of the countries in the world. Participants make quinquennial policy decisions on greenhouse gas emissions, recapture of CO2 from the atmosphere, and/or modification of the global albedo. Costs of climate change and of implementing policy decisions impact each region’s gross domestic product. Participants are tasked with maximizing economic benefits to their region while nearly stabilizing atmospheric CO2 concentrations by the end of the simulation in Julian year 2195. Results are shown where regions most adversely affected by effects of greenhouse gas emissions resort to increases in the earth’s albedo to reduce net solar insolation. These actions induce temperate region countries to reduce net greenhouse gas emissions. An example outcome is a trajectory to the year 2195 of atmospheric greenhouse emissions and concentrations, sea level, and global average temperature. Full article
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