Towards the Circular Soil Concept: Optimization of Engineered Soils for Green Infrastructure Application

At conventional construction sites, the removal of soil and other excavated materials causes enormous mass movement, with a significant climate impact and contribution to global CO2 release. This study aimed to generate a Circular Soil concept for reusing excavated materials by creating engineered soils for landscape construction at large building sites. Engineered soils act as a substitute for natural soils and fulfill vital technical and soil functions when installing an urban green infrastructure (GI). In a field study, the vegetation performance on engineered soils was evaluated to establish a methodological approach, to assess the applicability of the Circular Soil concept. First, the technical specifications (grain-size distribution) were modeled for intensive green roof and turfgrass applications. Then, the soil components were optimized, mixed, installed and tested for greenery purposes, focusing on plant growth performance indicators (vitality, projective cover ratio and grass-herb ratio) to assess the vegetation performance. The results showed that the engineered soils match the performance of the reference soil alternatives. In conclusion, the Circular Soil concept has a high potential to contribute considerably to sustainable on-site soil management and the circular economy. It can be applied on a larger scale for urban GI development and sustainable resources management in the landscaping and construction sector.

Tree Cover Ratio Effects on Users’ Perceptions, Impressions and Suitability Judgment for Different Activities in Privately Owned Public Spaces

People are drawn to natural settings because they instinctively associate them with providing, nurturing environments. Many studies have linked higher urban greenery ratios to social, psychological, economic, and human health improvements. While urban greenery benefits a large number of people, the monetary burden of its installation and maintenance falls typically to local governments or private entities, requiring urban designers to be able to justify the higher costs of implementation and maintenance. To date, there is still no precise data linking tree cover ratio and the specific effects it has on peoples’ perceptions and impressions of urban plazas or in the environment’s suitability for different activities. This study expands on the findings of previous studies to explore the effects of tree cover ratio and environment scale across twenty-three different evaluation scales. It used immersive virtual environments to control for confounding variables and head-mounted displays to present the stimuli, allowing participants to experience the environment in its totality as in a natural setting. Higher tree cover ratios improved participants’ willingness to stay and pay for goods, improved perception, impressions, and how suitable the environment was for different activities. The specific effects on five measurement scales for activities, nine measurement scales for impression and seven different measurement scales for perception are shown as well as the effects of the interaction of tree cover ratio and environment scale.The effects of sex and architectural background are also tested and discussed. Results offer designers with evidence for the definition of tree amount in relation to environment scale, based on the desired effect.

Detection of Stego Images with Adaptively Embedded Data by Component Analysis Methods

Ensuring the effective protection of personal and corporate sensitive data is topical task today. The special interest is taken at sensitive data leakage prevention during files transmission in communication systems. In most cases, these leakages are conducted by usage of advance adaptive steganographic methods. These methods are aimed at minimizing distortions of cover files, such as digital images, during data hiding that negatively impact on detection accuracy of formed stego images. For overcoming this shortcoming, it was proposed to pre-process (calibrate) analyzed images for increasing stego- to-cover ratio. The modern paradigm of image calibration is based on usage of enormous set of high-pass filters. However, selection of filter(s) that maximizes the probability of stego images detection is non-trivial task, especially in case of limited a prior knowledge about embedding methods. For solving this task, we proposed to use component analysis methods for image calibration, namely principal components analysis. Results of comparative analysis of novel maxSRMd2 cover rich model and proposed solution showed that principal component analysis allows increasing detection accuracy up to 1.5% even in the most difficult cases (low cover image payload and absence of cover- stego images pairs in training set).

Financial Leverage and Performance of the Energy and Petroleum Sector Companies Listed in the Nairobi Securities Exchange

Financial leverage and financial performance are fundamental issues in corporate finance. In Kenya, some companies listed at the Nairobi Securities Exchange have had performance improvement. However, most of them have experienced declining fortunes which has been attributed to the fact that corporate managers another practitioner lack adequate guidance required to attain optimal financing decisions. Financial leverage comprises of loans and other forms of debts where the proceeds from these loans are reinvested to earn higher return than the cost of loans. Financial use is the company's capacity to utilization of settled money related charges to amplify the impacts of changes in the profit before premium and duty on the company's income per share. The extent of obligation to value is a vital decision for corporate supervisors. The poor performance of Energy and Petroleum sector companies is of great concern. Financial leverage ranges from debt ratio, debt/equity ratio and interest coverage ratio which are vital since they directly affect the financial performance of firms. The general objective as to determine the effect of financial leverage on the financial performance of energy and petroleum sector companies listed in the NSE. While the specific objectives were; to establish the effect of debt ratio, debt -equity ratio and interest coverage ratio on financial performance of energy and petroleum sector companies recorded in the NSE. The research was anchored on the following theories: Modigliani-Miller theorem, Pecking Order Theory and Trade-off Theory. The empirical literature review was based on the three objectives of the study and gaps established. The study adopted a descriptive research design. Management of all the 5 energy and petroleum companies listed with the NSE was involved in the study which mainly used secondary data to conclude. Data was analyzed using regression analysis. Analyzed data was presented using tables. Confidence interval of 95% was used by the researcher. The study adopted a multiple regression model (Y = β0 + β1X1 + β2X2 + β3X3 +ε). The findings indicate that the independent variables Debt ratio, Debt to Equity ratio and interest cover ratio affected the financial performance of the firms in the Energy and petroleum sector. Their effect was up to 75.4%. Debt ratio and Debt to Equity ratio had a positive relationship whereas Interest cover ratio had a negative relationship to the firms in the Energy and petroleum sector listed in the NSE. This study recommends that the firms handle their capital structure decisions prudently as the changes in the factors like Debt ratio, Debt to Equity ratio and Interest cover ratio enhance profitability of firms when prudently employed and hence affect the performance of Energy and petroleum firms listed at the Nairobi Securities Exchange. This study also recommends that firms control the amount of interest expense since an increase in interest expense has an effect in that it reduces the financial performance of firms in the Energy and petroleum sector listed in the NSE.

RADT-05. PROSPECTIVE LONG-TERM EVALUATION OF MRI- AND CLINICAL CHANGES FOLLOWING STEREOTACTIC RADIOSURGERY FOR BRAIN METASTASES – IS REPEAT SRS A CONSEQUENCE, OR ALSO A CAUSE OF LONG-TERM SURVIVAL?

The use of stereotactic radiosurgery (SRS) for brain metastases are increasing. Response assessment is challenging and the clinical significance of radiological response and retreatments are poorly defined. Ninety-seven patients with a total of 406 brain metastases were followed prospectively for 10 years or until death. Volume changes over time and clinical outcome in response to first time SRS and SRS retreatments were analyzed. Tumors grew significantly before (p = 0.004), but shrunk at 1 and 3 months (p = 0.001) following SRS. Four response-patterns of were observed; tumors either continuously reduced in size (A, 62%), pseudo-progressed (PP, B, 13%), temporarily reduced in size (C, 24%), or grew continuously (D, 2%); corresponding to 75% local control (LC) at initial SRS. Predictors for LC were primary cancer site (p = 0.001), tumor volume (p = 0.002) and target cover ratio (p = 0.005). Subsequent SRS for new lesions resulted in 94% LC (87% A) and repeat-SRS for local failures in 80% LC (57% B), predicted by higher prescribed dose, p = 0.001 and p = 0.042, respectively. Overall survival was only 4.5 months if A-response for all lesions, 13.3 months if at least one B-response, 17.1 months if retreated C- or D-response (p < 0.001), (7.5 and 4.7 months if untreated). Quality of life (p = 0.003), steroid use (p = 0.019) and prior whole brain radiotherapy (p = 0.026) were predictors for survival. There are 4 response patterns to SRS predicted by tumor size, primary cancer site, target cover ratio and prescribed dose. Long-term survivors experienced a higher incidence of PP and were more often retreated for new lesions and local failures. The immune response induced by PP seems beneficial but further studies are needed.

Alternative Engineered Soils and Seed Mixes Used for Seepage Troughs

Green Infrastructure measures such as seepage troughs are an integral part of sustainable urban rainwater management. In Austria, seepage troughs are currently almost exclusively produced with a 30 cm thick active soil filter passage made of topsoil. A standard seed mix is used as vegetation, which usually consists of only three different turfgrass species. During a three-year trial, engineered soils with improved properties (increased water storage capacity, infiltration rate and pore volume) were tested for their suitability as seepage troughs compared to topsoil. In addition to the standard turf seed mix, a flowering turf seed mix (34 species) and flowering meadow seed mix (53 species) were applied. The engineered and reference soils were analyzed for infiltration rate, vitality, cover ratio and inflorescence. The results were further assessed with the evaluation chart showing quantitatively the suitability of the tested soils for rainwater management. The investigations showed that engineered soils in combination with flowering meadow seed mix lead to the best results. Therefore, this type of vegetation for seepage troughs is recommended for future applications. The reference alternatives cannot be recommended.

Optimum Energy Flow Management of a Grid-Tied Photovoltaic-Wind-Battery System considering Cost, Reliability, and CO2 Emission

The main goal of this paper is to explore the performance of a residential grid-tied hybrid (GTH) system which relies on economic and environmental aspects. A photovoltaic- (PV-) wind turbine- (WT-) battery storage system with maximizing self-consumption and time-of-use (ToU) pricing is conducted to examine the system efficiency. In so doing, technical optimization criteria with taking into consideration renewable energy benefits including feed-in-tariff (FIT) and greenhouse gas emission (GHG) reduction are analyzed. As the battery has a substantial effect on the operational cost of the system, the energy management strategy (EMS) will incorporate the daily operating cost of the battery and the effect of the degradation. The model can give the opportunity to the network to sell or purchase energy from the system. The simulation results demonstrate the effectiveness of the proposed approach in which the new objective function achieves the maximum cost-saving (99.81%) and income (5.16 $/day) compared to other existing strategies as well as the lowest GHG emission. Furthermore, the battery enhances the best daily self-consumption and load cover ratio. Then, as the model is nonlinear, a comparison with other existing algorithms is performed to select the feasible, robust, and reliable model for the residential application. A hybrid algorithm (HGAFMINCON) is developed to demonstrate the superiority of the algorithm over FMINCON and GA shown in terms of cost savings and income.

Assessment of the possibility of surgical masks re-use after a sterilization process in the pandemic condition of COVID-19

The aim of this study was to explore the possibility to re-use disposable masks in order to prevent excessive waste generation during the pandemic period. The COVID-19 pandemic has caused rapidly increasing waste production resulting from the necessity of common usage of disposable personal protective equipment. This research covers the evaluation of the structure of surgical masks subjected to a threefold steam, gas or plasma sterilization process in order to verify the possibility of their re-use. The results of the study showed that gas sterilization even after three cycles did not cause significant changes in mask structure or air permeability. Hydrogen peroxide plasma sterilization caused significant changes in the structure of layer A after the third cycle of sterilization; nonetheless, it did not influence the air permeability of the mask. A significant reduction in the cover ratio of layers composing surgical masks causes an increase of air permeability in the case of steam sterilization, leading to a reduction of the mechanical ability to prevent the penetration of microorganisms. The reduction in cover ratio limits the filtration efficiency. Surgical masks subjected to threefold gas sterilization can be recommended for re-use. This allows one to use the mask thrice, ensuring safety for users and limiting the mask-waste production to one-third of the volume compared with when the mask is used once. The volume of mask-waste can be reduced with the application of the sterilization process for used masks during the pandemic period. Currently, it is not possible to sterilize all one-use masks, but implementation of this method in hospitals and medical centers is a step in the pro-environmental direction.

Spatial distribution of Culex mosquito abundance and associated risk factors in Hanoi, Vietnam

Japanese encephalitis (JE) is the major cause of viral encephalitis (VE) in most Asian-Pacific countries. In Vietnam, there is no nationwide surveillance system for JE due to lack of medical facilities and diagnoses. Culex tritaeniorhynchus, Culex vishnui, and Culex quinquefasciatus have been identified as the major JE vectors in Vietnam. The main objective of this study was to forecast a risk map of Culex mosquitoes in Hanoi, which is one of the most densely populated cities in Vietnam. A total of 10,775 female adult Culex mosquitoes were collected from 513 trapping locations. We collected temperature and precipitation information during the study period and its preceding month. In addition, the other predictor variables (e.g., normalized difference vegetation index [NDVI], land use/land cover and human population density), were collected for our analysis. The final model selected for estimating the Culex mosquito abundance included centered rainfall, quadratic term rainfall, rice cover ratio, forest cover ratio, and human population density variables. The estimated spatial distribution of Culex mosquito abundance ranged from 0 to more than 200 mosquitoes per 900m2. Our model estimated that 87% of the Hanoi area had an abundance of mosquitoes from 0 to 50, whereas approximately 1.2% of the area showed more than 150 mosquitoes, which was mostly in the rural/peri-urban districts. Our findings provide better insight into understanding the spatial distribution of Culex mosquitoes and its associated environmental risk factors. Such information can assist local clinicians and public health policymakers to identify potential areas of risk for JE virus. Risk maps can be an efficient way of raising public awareness about the virus and further preventive measures need to be considered in order to prevent outbreaks and onwards transmission of JE virus.

INFLUENCE OF DIGITAL IMAGES PRELIMINARY NOISING ON STATISTICAL STEGDETECTORS PERFORMANCE

Context. The problem of sensitive information protection during data transmission in communication systems was considered. The case of reliable detection of stego images formed according to advanced embedding methods was investigated. The object of research is digital images steganalysis of adaptive steganographic methods. Objective. The goal of the work is performance analysis of statistical stegdetectors for adaptive embedding methods in case of preliminary noising of analyzed image with thermal and shot noises. Method. The image pre-processing (calibration) method was proposed for improving stego-to-cover ratio for state-of-the-art adaptive embedding methods HUGO, MG and MiPOD. The method is aimed at amplifying negligible changes of cover image caused by message hiding with usage of Gaussian and Poisson noises. The former one is related to influence the thermal noise of chargecoupled device (CCD) based image sensor during data acquisition. The latter one is related to shot noise that originates from stochastic process of electron emission by photons hitting of CCD elements. During the research, parameters of thermal noise were estimated with two-dimensional Wiener filter, while sliding window of size 5·5 pixels was used for parameters evaluation for shot noise. Results. The dependencies of detection error on cover image payload for advance HUGO, MG and MiPOD embedding methods were obtained. The results were presented for the case of image pre-noising with both Gaussian and Poisson noises, and varying of feature pre-processing methods. Conclusions. The conducted experiments confirmed effectiveness of proposed approach for image calibration with Poisson noise. Obtained results allow us to recommend linearly transformed features to be used for improving stegdetector performance by natural image processing. The prospects for further research may include investigation usage of special noises, such as fractal noises, for improving stego-to-cover ratio for advanced embedding methods.