bluuebunny/crossref_metadata_2025 huggingface dataset:
Viral hepatitis among men who have sex with men, epidemiology and public health consequences
Authors: Urbanus A T , van Houdt R , van de Laar T JW , Coutinho R  A
Published: November 2017

Viral hepatitis causes major disease burden worldwide, due to the chronic hepatitis sequelae: cirrhosis and primary liver cancer. Transmission of viral hepatitis is a problem not only in low-income countries, but also in high-income ones where viral hepatitis is a frequently occurring infection among men who have sex with men (MSM). Although the transmission routes of the three main hepatitis viruses, A, B and C, differ, MSM mainly acquire viral hepatitis during sexual contact. Vaccination programmes (only available for hepatitis A and B), raising awareness, and screening can be used to prevent transmission. However, despite the introduction of such methods in many high-income countries, the spread of viral hepatitis among MSM is still ongoing. This paper provides an overview of sexually acquired hepatitis A, B, and C among MSM in high-income countries, using recent insights obtained through molecular epidemiology, with the aim to raise awareness, improve vaccination coverage, and stimulate prevention programs.
Accounting Information Systems Effectiveness: Evidence from the Nigerian Banking Sector
Authors: Ladan Shagari Shamsudeen , Abdullah Akilah , Mat Saat Rafeah
Published: December 2017

Aim/Purpose: The purpose of this study is to investigate the interrelationship among the quality measures of information system success, including system quality, information, quality, and service quality, that eventually influence accounting information systems effectiveness.

Background: It is generally believed that investment in an information system offers opportunities to organizations for business process efficiency and effectiveness. Despite huge investments in accounting information systems, banks in Nigeria have not realized the full potential benefits of using these systems because of persistent failures. Few studies have been conducted to address the problem.

Methodology: A survey research design was used to collect data, and a total of 287 questionnaires were retrieved from respondents in the Nigerian banking sector.

Contribution: This study contributes to the understanding of the most important antecedent factors of the quality measures, the interrelationship among the quality measures, and the influence of these measures on the accounting information systems effectiveness.

Findings: The result of the study revealed that security, ease of use, and efficiency are key features of system quality, while the information quality dimension includes accuracy, timeliness, and completeness. The result of the study further revealed that information quality and system quality have significant influences on accounting information systems effectiveness.

Recommendations for Practitioners: This study provides practitioners with important measures for evaluation of AIS effectiveness in the context of Nigerian banks.

Recommendation for Researchers: Future researchers may build on the findings of current study to conduct fur-ther research in the area of AIS effectiveness in different contexts.

Future Research: This study examines only three quality measures of Delone and Mclean model and antecedents of information and system quality measures, neglecting contingency factor. Therefore, future study should include other factors to the AIS effectiveness model to help in developing more specific theory in AIS domain.
MITOS E FATOS DE RELATOS GERENCIAIS SOB O OLHAR DA TEORIA CRÍTICA
Authors: Alves Filho Luiz Da Costa
Published: December 2017

Este estudo tem como objetivo analisar os relatos dos gestores de micro e pequenas empresas de João Pessoa-PB sob a perspectiva da Teoria Crítica, discutindo aspectos destes relatos associados aos mitos e fatos defendidos por Mintzberg (1990). A fundamentação teórica aborda três aspectos centrais: a importância da ciência da administração nos contextos teórico e prático; os mitos e fatos gerenciais e; a perspectiva da Teoria Crítica (TC) e suas reflexões no âmbito organizacional. Participaram da pesquisa 12 gestores, divididos em: graduados em administração, outra graduação e gestores sem formação superior. Foram realizadas entrevistas semiestruturadas, sendo, posteriormente, analisadas por meio da análise de conteúdo. Os resultados revelaram alguns aspectos peculiares entre os grupos de entrevistados, tais como: a necessidade dos mesmos em ter auto responsabilidade dentro e fora da empresa para buscar as informações e os conhecimentos necessários para garantir a sua sobrevivência ou ascensão no mercado atuante. Além disso, verificou-se que a abertura da gestão frente às propostas, sugestões ou críticas dos funcionários é um aspecto fundamental para tornar o ambiente de trabalho um lugar mais democrático e favorável às discussões pertinentes aos interesses de todos os colaboradores.  This study aims to analyze the reports of the managers of micro and small enterprises of João Pessoa-PB from the perspective of Critical Theory, discussing aspects of these reports associated to the myths and facts defended by Mintzberg (1990). The theoretical framework addresses three main aspects: the importance of management science in theoretical and practical contexts; the myths and facts and management and; the perspective of Critical Theory (CT) and its reflections on the organizational level. The participants were 12 managers, divided into: managers degree in business administration, with other graduate and managers without higher education. Semi-structured interviews, and later analyzed using content analysis were performed. The results revealed some peculiar aspects of the interview groups, such as the need for them to have self-responsibility inside and outside the company to find the information and knowledge needed to ensure their survival or rise in the active market and the sense of constant learning. Furthermore, it was found that opening the front to management proposals, suggestions or criticisms of the employees is a key aspect to make the workplace a more democratic and favorable place to discussions relevant to the interests of all employees.
FERMENTASI MENGGUNAKAN RAGI TEMPE SEBAGAI CARA BIOLOGIS PENGAPUNGAN PAKAN IKAN
Authors: Leiskayanti Yesi , Sriherwanto Catur , Suja'i Imam
Published: December 2017

Fermentation Using Tempe Starter as A Biological Method for Providing Buoyancy to Fish FeedABSTRACTRhizopus sp. is known as the fungus in the making of the soybean tempeh, Rhizopus sp. fermentation brought about chemical as well as physical changes on the substrate including the buoyancy and water stability. These features may be used to biologically prepare floating aquafeed. In this study, tempeh starter was used as the biological agent in the fermentation of commercial sinking fish feed in which fermentation period was varied at 0, 22, 24, 26, 28, 30, 32, and 34 hours. The resulting fermented feeds were oven-dried and their physical qualities were measured and compared to the commercial floating fish feed (positive control). Results showed that the fermented feed gained better water stability, absorption capacity, and floatability compared to those of the commercial sinking feed. These values were however still lower than those of the commercial floating feeds. Thus, fermentation process using tempeh mould has potential to be further improved as a biological method of producing floating fish feed. Keywords: fermentation, floatability, Rhizopus sp., water absorption,  water stability ABSTRAKRhizopus sp. dikenal sebagai jamur yang digunakan dalam pembuatan tempe kedelai. Fermentasi Rhizopus sp. menyebabkan perubahan kimia dan fisika pada substrat, termasuk daya apung dan stabilitas dalam air. Sifat ini bisa dimanfaatkan untuk membuat pakan ikan apung secara biologis. Dalam penelitian ini, ragi tempe digunakan sebagai agen hayati dalam fermentasi pakan ikan tenggelam komersial dimana periode fermentasi divariasi selama 0, 22, 24, 26, 28, 30, 32, dan 34 jam. Pakan fermentasi yang dihasilkan dikeringkan dengan oven, selanjutnya kualitas fisiknya diukur dan dibandingkan dengan pakan ikan apung komersial (kontrol positif). Hasil penelitian menunjukkan bahwa pakan fermentasi memiliki stabilitas dalam air, daya serap air, dan daya apung yang lebih baik dibandingkan dengan pakan tenggelam komersial. Namun nilai ini masih lebih rendah dibandingkan pakan apung komersial. Oleh karenanya, proses fermentasi menggunakan ragi tempe memiliki potensi untuk diperbaiki lebih lanjut sebagai metode biologis pembuatan pakan ikan apung. Received: 11 October 2017                 Accepted: 07 November 2017              Published: 04 December 2017Kata Kunci: daya apung, daya serap air, fermentasi, Rhizopus sp., stabilitas dalam air
Toxicity of Checkpoint Inhibition in Advanced RCC: A Systematic Review
Authors: Ornstein Moshe C. , Garcia Jorge A.
Published: November 2017

Background:

Checkpoint inhibitors (CPI) have now been established as standard agents in the management of patients with metastatic renal cell carcinoma (mRCC). Given the unique toxicity profiles of CPIs, a detailed understanding of their incidence rate and characteristics is critical.

Objective:

To perform a systematic review for the analysis of the incidence rate and characteristics of toxicities in mRCC patients treated with CPIs in published clinical trials.

Methods:

A systematic search of EMBASE (Ovid) and MEDLINE (Ovid) was conducted as per PRISMA guidelines to identify prospective clinical trials of checkpoint inhibitors in mRCC. The search method involved querying for the terms renal cell carcinoma or kidney carcinoma with any of the following: programmed cell death 1, PD-1, programmed cell death ligand 1, PD-L1, cytotoxic T-lymphocyte antigen 4, CTLA-4, immunotherapy, checkpoint inhibitor, anti-PD-1, or anti-PD-L1. Only prospective clinical trials were included.

Results:

The systematic review yielded 9,722 records through the MEDLINE (Ovid) and EMBASE (Ovid) databases. Ultimately, five prospective clinical trials with 722 patients were selected for inclusion. The rates of any grade adverse event (AE) and grade (G) 3-4 AEs were 79.9% and 20.9%, respectively. Regarding immune-related AEs (irAEs), the most common system affected by any grade irAE was the skin (30.89%) and the most common grade 3-4 irAE was related to the hepatic system (8.23%). Rates of AEs were similar across the CPI monotherapy clinical trials.

Conclusions:

The rates of AEs in mRCC patients treated with CPI is similar to rates in other cancers. AEs in mRCC are fairly consistent among monotherapy trials with PD-1 and PD-L1 inhibitors and as one would expect higher when CTLA-4 and PD-1 inhibitors are offered in combination.
Improved Integral Inequalities for Stability Analysis of Interval Time-Delay Systems
Authors: Zhang Shuai , Qi Xiao
Published: December 2017

A novel stability analysis for the interval time-delay systems is proposed by employing a new series of integral inequalities for single and double integrals. Different from the recently introduced Wirtinger-based inequalities, refined Jensen inequalities and auxiliary function-based inequalities, the proposed ones can provide more accurate bounds for the cross terms in derivatives of the Lyapunov–Krasovskii functional (LKF) without involving additional slack variables. Based on the augmented LKF with triple-integral terms, their applications to stability analysis for interval time-delay systems are provided. By virtue of the newly derived inequalities, the resulting criteria are less conservative than some existing literature. Finally, numerical examples are provided to verify the effectiveness and improvement of the proposed approaches.
The Analysis of the Cause-Effect Relation between Tractor Overturns and Traumatic Lesions Suffered by Drivers and Passengers: A Crucial Step in the Reconstruction of Accident Dynamics and the Improvement of Prevention
Authors: Moreschi Carlo , Da Broi Ugo , Cividino Sirio , Gubiani Rino , Pergher Gianfranco , Vello Michela , Rinaldi Fabiano
Published: December 2017

The evaluation of the dynamics of accidents involving the overturning of farm tractors is difficult for both engineers and coroners. A clear reconstruction of the causes, vectorial forces, speed, acceleration, timing and direction of rear, front and side rollovers may be complicated by the complexity of the lesions, the absence of witnesses and the death of the operator, and sometimes also by multiple overturns. Careful analysis of the death scene, vehicle, traumatic lesions and their comparison with the mechanical structures of the vehicle and the morphology of the terrain, should help experts to reconstruct the dynamics of accidents and may help in the design of new preventive equipment and procedures.
Assessing the Impacts of Large-Scale Agro-Industrial Sugarcane Production on Biodiversity: A Case Study of Wonji Shoa Sugar Estate, Ethiopia
Authors: Degefa Sileshi , Saito Osamu
Published: December 2017

Despite the intense debates on the land acquisition effects of large-scale Ethiopian sugarcane plantations and the consequences for food security, the impact on biodiversity has received less attention. We compared remnant patches in the sugarcane zone to the adjacent woodlands to determine the impacts of sugarcane on the diversity, composition, and structure of woody species. We recorded individual woody specimens with diameter at breast height (DBH) ≥ 2.5 cm from 56 quadrats of 200 m2 at each site in a systematic, random, and gradient-oriented transect design. In addition, we employed a trait-based risk assessment framework to examine the threat posed by agro-industrial sugarcane production on mammals, birds, and rodents. A total of 56 woody species, 38 in the woodlands and 30 in the sugarcane zone, were identified. The proportion of non-native woody species was higher (63%) in the sugarcane zone than in the adjacent woodlands (1%). The rodents and mammals were more abundant in the woodlands than in the sugarcane zone. Although we did not investigate all of the bird and mammal species, our results identified six rodent species, five mammal species, and one bird species as susceptible to sugarcane agriculture activities. The results suggest that large-scale agro-industrial sugarcane production impacts species diversity, composition and abundance of species, and species’ resource requirements.
Using Free Adoptions to Reduce Crowding and Euthanasia at Cat Shelters: An Australian Case Study
Authors: Crawford Heather M. , Fontaine Joseph B. , Calver Michael C.
Published: December 2017

Many healthy adult cats are euthanised annually in shelters, and novel approaches are required to reduce euthanasia rates. Waiving adoption fees is one such approach. However, concerns that less responsible owners will be attracted to free events persist among welfare groups. We evaluated evidence for differences in cat fate, health, and adherence to husbandry legislation via a case-study of a free adoption-drive for cats ≥1 year at a Western Australian shelter. Post-adoption outcomes were compared between free adopters and a control group of normal-fee adopters. The free adoption-drive rehomed 137 cats, increasing average weekly adoptions by 533%. First-time adopters were a significantly larger portion of the free cohort, as a result of mixed-media promotions. Both adopter groups selected cats of similar age; sex and pelage. Post-adoption, both groups retained >90% cats, reporting near identical incidences of medical and behavioural problems. Adopters did not differ in legislative compliance regarding fitting collars, registering cats, or allowing cats to roam. The shelter reported satisfaction with the adoption-drive, because in addition to relieving crowding of healthy adults, adoption of full-fee kittens increased 381%. Overall, we found no evidence for adverse outcomes associated with free adoptions. Shelters should not be dissuaded from occasional free adoption-drives during overflow periods.
Consciousness Is a Thing, Not a Process
Authors: Pockett Susan
Published: December 2017

The central dogma of cognitive psychology is ‘consciousness is a process, not a thing’. Hence, the main task of cognitive neuroscientists is generally seen as working out what kinds of neural processing are conscious and what kinds are not. I argue here that the central dogma is simply wrong. All neural processing is unconscious. The illusion that some of it is conscious results largely from a failure to separate consciousness per se from a number of unconscious processes that normally accompany it—most particularly focal attention. Conscious sensory experiences are not processes at all. They are things: specifically, spatial electromagnetic (EM) patterns, which are presently generated only by ongoing unconscious processing at certain times and places in the mammalian brain, but which in principle could be generated by hardware rather than wetware. The neurophysiological mechanisms by which putatively conscious EM patterns are generated, the features that may distinguish conscious from unconscious patterns, the general principles that distinguish the conscious patterns of different sensory modalities and the general features that distinguish the conscious patterns of different experiences within any given sensory modality are all described. Suggestions for further development of this paradigm are provided.
Effect of Equal Channel Angular Pressing (ECAP) on Erosion-Corrosion of Pure Copper
Authors: Irfan Osama M. , Al-Mufadi Fahad , Al-Shataif Yaser , Djavanroodi Faramarz
Published: December 2017

During the past few decades, ultrafine-grained materials (UFG) have experienced rapid development. Enhanced mechanical and surface properties, such as strength, ductility and erosion-corrosion (E-C) resistance by refining the grain to ultra-fine/nanometer size has been achieved. The equal channel angular pressing (ECAP) is a popular severe plastic deformation (SPD) method to fabricate UFG bulk materials. In this research, the E-C behavior of commercial annealed pure copper subject to four passes of ECAP have been investigated. Hardness measurement of the copper specimen after four passes of ECAP showed an increase of 200% on the hardness value as compared with annealed condition. Simulated seawater was used as an E-C medium. The effect of different E-C parameters such as time, slurry flow velocity, impact angle, and solid particle concentration on ECAP process is studied. The results showed that ECAP enhances the E-C resistance of copper, and this behavior improves with increasing the pass number. Generally, a 30% rise in resistance to E-C was achieved after four ECAP passes as compared to coarse grain copper for the parameters studied in this work. Optical microscopy was used to examine the microstructure and material removal mechanism of the annealed copper. Scanning electron microscopy (SEM) was used to validate the reduction of grain size due to ECAP process. Furthermore, examination of the surface roughness of the copper at different ECAP passes showed that for the same E-C condition the increment of ECAP passes leads to a smoother surface.
Non-Destructive Infrared Evaluation of Thermo-Physical Parameters in Bamboo Specimens
Authors: Ospina-Borras Juan , Benitez-Restrepo Hernán , Florez-Ospina Juan
Published: December 2017

The estimation of heat conduction properties has considerable importance in the characterization of bamboo with respect to its potential use as an alternative construction material. Even though traditional methods such as hot plates have successfully measured thermal parameters, like thermal diffusivity and conductivity in bamboo samples, it is still necessary to transform the cylindrical bamboo specimen into a piece with special geometry and size. This requirement makes this method impractical in applications where several bamboo specimens need to be measured in their original cylindrical shape. This paper presents the estimation of thermo-physical parameters k and ρ c p in Guadua angustifolia kunth (Guadua a.k.) bamboo through nonlinear least square optimization and infrared thermography. A sensitivity analysis was carried out to determine how the temperature on the bamboo surface is affected by changes in the convection coefficient h, thermal conductivity k, and volumetric heat capacity ρ c p . In spite of the nonlinearity and high correlation in the parameters of the inverse heat conduction problem (IHCP), the estimation of such parameters is robust and consistent with those reported in the literature.
Off-Line Optimization Based Active Control of Torsional Oscillation for Electric Vehicle Drivetrain
Authors: Lin Cheng , Sun Shengxiong , Walker Paul , Zhang Nong
Published: December 2017

As there is no clutch or hydraulic torque converter in electric vehicles to buffer and absorb torsional vibrations. Oscillation will occur in electric vehicle drivetrains when drivers tip in/out or are shifting. In order to improve vehicle response to transients, reduce vehicle jerk and reduce wear of drivetrain parts, torque step changes should be avoided. This article mainly focuses on drivetrain oscillations caused by torque interruption for shifting in a Motor-Transmission Integrated System. It takes advantage of the motor responsiveness, an optimal active control method is presented to reduce oscillations by adjusting motor torque output dynamically. A rear-wheel-drive electric vehicle with a two gear automated manual transmission is considered to set up dynamic differential equations based on Newton’s law of motion. By linearization of the affine system, a joint genetic algorithm and linear quadratic regulator method is applied to calculate the real optimal motor torque. In order to improve immediacy of the control system, time consuming optimization process of parameters is completed off-line. The active control system is tested in AMEsim® and limitation of motor external characteristics are considered. The results demonstrate that, compared with the open-loop system, the proposed algorithm can reduce motion oscillation to a satisfied extent when unloading torque for shifting.
Enhanced MODIS Atmospheric Total Water Vapour Content Trends in Response to Arctic Amplification
Authors: Alraddawi Dunya , Keckhut Philippe , Sarkissian Alain , Bock Olivier , Irbah Abdanour , Bekki Slimane , Claud Chantal , Meftah Mustapha
Published: December 2017

In order to assess the strength of the water vapour feedback within Arctic climate change, 15 years of the total column-integrated density of water vapour (TCWV) from the moderate resolution imaging spectrometer (MODIS) are analysed. Arctic TCWV distribution, trends, and anomalies for the 2001–2015 period, broken down into seasons and months, are analysed. Enhanced local spring TCWV trends above the terrestrial Arctic regions are discussed in relation to land snow cover and vegetation changes. Upward TCWV trends above the oceanic areas are discussed in lien with sea ice extent and sea surface temperature changes. Increased winter TCWV (up to 40%) south of the Svalbard archipelago are observed; these trends are probably driven by a local warming and sea ice extent decline. Similarly, the Barents/Kara regions underwent wet trends (up to 40%), also associated with winter/fall local sea ice loss. Positive late summer TCWV trends above the western Greenland and Beaufort seas (about 20%) result from enhanced upper ocean warming and thereby a local coastal decline in ice extent. The Mackenzie and Siberia enhanced TCWV trends (about 25%) during spring are found to be associated with coincident decreased snow cover and increased vegetation, as a result of the earlier melt onset. Results show drier summers in the Eurasia and western Alaska regions, thought to be affected by changes in albedo from changing vegetation. Other TCWV anomalies are also presented and discussed in relation to the dramatic decline in sea ice extent and the exceptional rise in sea surface temperature.
Evaluation of House Rent Prices and Their Affordability in Port Moresby, Papua New Guinea
Authors: Ezebilo Eugene
Published: December 2017

Access to affordable housing has been a long-standing issue for households in most cities. This paper reports on a study of house rent prices in Port Moresby, factors influencing them, and affordability of the prices. Data was obtained from houses that were advertised for rent in Port Moresby for a period of 13 months and were analysed using the ordinary least squares (OLS) regression model. The results show that monthly house rent prices range from 2357 to 34,286 Papua New Guinea Kina (PGK), or 714 to 10,389 U.S. dollars (USD), and the median price was 7286 PGK (2208 USD). Houses located in the central business district had the highest median house rent price, whereas low-income areas had the lowest rent price. By dividing the median house rent price by gross household income, the housing affordability index was 3.4. House rent price was influenced by factors such as number of bedrooms and location. To make house rent prices more affordable for Port Moresby residents, it is necessary to supply more houses for rent relative to demand, especially in low-income areas. Relevant governmental agencies should put more effort toward unlocking more customarily-owned land for housing development and toward facilitating the private sector to construct more low-cost houses for rent, which are affordable for low to middle income households. This has the potential of improving Port Moresby residents’ access to affordable houses for rent. The findings could assist urban development managers and planners in allocating resources for housing by considering housing demand, supply, and house rent prices.
Low-Temperature Sol-Gel Synthesis of Nitrogen-Doped Anatase/Brookite Biphasic Nanoparticles with High Surface Area and Visible-Light Performance
Authors: Jiang Liang , Li Yizhou , Yang Haiyan , Yang Yepeng , Liu Jun , Yan Zhiying , Long Xiang , He Jiao , Wang Jiaqiang
Published: December 2017

Nitrogen doping in combination with the brookite phase or a mixture of TiO2 polymorphs nanomaterials can enhance photocatalytic activity under visible light. Generally, nitrogen-dopedanatase/brookite mixed phases TiO2 nanoparticles obtained by hydrothermal or solvothermal method need to be at high temperature and with long time heating treatment. Furthermore, the surface areas of them are low (<125 m2/g). There is hardly a report on the simple and direct preparation of N-doped anatase/brookite mixed phase TiO2 nanostructures using sol-gel method at low heating temperature. In this paper, the nitrogen-doped anatase/brookite biphasic nanoparticles with large surface area (240 m2/g) were successfully prepared using sol-gel method at low temperature (165 °C), and with short heating time (4 h) under autogenous pressure. The obtained sample without subsequent annealing at elevated temperatures showed enhanced photocatalytic efficiency for the degradation of methyl orange (MO) with 4.2-, 9.6-, and 7.5-fold visible light activities compared to P25 and the amorphous samples heated in muffle furnace with air or in tube furnace with a flow of nitrogen at 165 °C, respectively. This result was attributed to the synergistic effects of nitrogen doping, mixed crystalline phases, and high surface area.
Intensity of Urban Heat Islands in Tropical and Temperate Climates
Authors: Amorim Margarete , Dubreuil Vincent
Published: December 2017

Nowadays, most of the Earth’s population lives in urban areas. The replacement of vegetation by buildings and the general soil sealing, associated with human activity, lead to a rise in cities temperature, resulting in the formation of urban heat islands. This article aims to evaluate the intensity and the hourly maintenance of the atmospheric heat islands in two climates: one tropical (Presidente Prudente, Brazil) and one temperate (Rennes, France) throughout 2016. For this, air temperature and hourly averages were measured and calculated using both a HOBO datalogger (U23-002—protected under the same RS3 brand) and weather stations Davis Vantage PRO 2. The daily evolution of the heat islands presented characteristics that varied according to the hours and seasons of the year. For both Rennes and Presidente Prudente, the largest magnitudes occurred overnight, being more greatly expressed in the tropical environment and during the driest months (winter in the tropical city and summer in the temperate one). The variability of synoptic conditions from one month to another also leads to a great heterogeneity of UHI intensity throughout the year.
Exploring Chemistry Student Teachers’ Diagnostic Competence—A Qualitative Cross-Level Study
Authors: Tolsdorf Yannik , Markic Silvija
Published: December 2017

Diagnostic competence is an important skill of professional teachers and is a part of Pedagogical Content Knowledge (PCK). Because increasing heterogeneity and diversity characterize our schools, diagnostic competence plays a prominent role in teacher pre- and in-service courses. At our university, two modules are focused on examining student teachers’ diagnostic competence in chemistry. The present paper describes a cross-level case study analyzing three groups of student teachers in different phases of their university teacher training program. The study is based on a qualitative research study with a total of 108 participants. The results show both positive and negative developments in teacher trainees’ diagnostic competence. They show that attitudes and beliefs about heterogeneity can be changed from a rather negative viewpoint to a more positive one. The results will be presented and discussed below. Suggestions for further development will be given.
South Korean Household’s Willingness to Pay for Replacing Coal with Natural Gas? A View from CO2 Emissions Reduction
Authors: Lim Seul-Ye , Kim Hyo-Jin , Yoo Seung-Hoon
Published: December 2017

Coal is currently a major electric power generation source in South Korea when considering that forty-three percent of electricity that was generated during the first quarter of 2017 came from coal. The amount of CO2 emissions from coal-fired power plant is two times larger than that from natural gas (NG)-fired power plant in the country. In this regard, the Korean government is trying to replace some amount of coal that is used for generation with NG to reduce CO2 emissions. However, the cost of NG-fired generation is about 1.25 times higher than that of coal-fired generation. Thus, the policy-makers demand information about the household willingness to pay (WTP) for the replacement to mitigate CO2 emissions. This paper applies the contingent valuation (CV) approach, and assesses the household’s WTP for replacing one kWh of coal-fired power with that of NG-fired power. For this purpose, a total of 1000 South Korean households were involved in the CV survey employing a dichotomous choice question. In addition to the current electricity price, KRW 121.52 (USD 0.11) per kWh, the respondents were willing to pay KRW 25.35 (USD 0.02) per kWh. The costs of NG-fired and coal-fired generation are KRW 100.13 and 78.05, respectively, per kWh. The difference between the two is KRW 22.08 per kWh, which is smaller than the mean additional WTP (KRW 25.35 per kWh). The household’s additional WTP is bigger than the actual additional cost. It is concluded that the switch of power generation source from coal to NG to reduce CO2 emissions can be supported by South Korean households.
Control Algorithms of Shunt Active Power Filter for Harmonics Mitigation: A Review
Authors: Hoon Yap , Mohd Radzi Mohd , Hassan Mohd , Mailah Nashiren
Published: December 2017

Current harmonics is one of the most significant power quality issues which has attracted tremendous research interest. Shunt active power filter (SAPF) is the best solution to minimize harmonic contamination, but its effectiveness is strictly dependent on how quickly and accurately its control algorithms can perform. This manuscript reviews various types of existing control algorithms which have been employed for controlling operation of SAPF. Harmonic extraction, DC-link capacitor voltage regulation, current control and synchronizer algorithms are examined and discussed. The most relevant techniques which have been applied for each control algorithm are described and contrasted in an organized manner to identify their respective strengths and weaknesses. It is found that the applied control algorithms differ in two conditions: (1) the condition where harmonic current distortion is treated by the SAPF in the presence of non-ideal source voltage; and (2) the condition where multilevel inverter is employed as the circuit topology of SAPF.
Energy Production Analysis and Optimization of Mini-Grid in Remote Areas: The Case Study of Habaswein, Kenya
Authors: Micangeli Andrea , Del Citto Riccardo , Kiva Isaac , Santori Simone , Gambino Valeria , Kiplagat Jeremiah , Viganò Daniele , Fioriti Davide , Poli Davide
Published: December 2017

Rural electrification in remote areas of developing countries has several challenges which hinder energy access to the population. For instance, the extension of the national grid to provide electricity in these areas is largely not viable. The Kenyan Government has put a target to achieve universal energy access by the year 2020. To realize this objective, the focus of the program is being shifted to establishing off-grid power stations in rural areas. Among rural areas to be electrified is Habaswein, which is a settlement in Kenya’s northeastern region without connection to the national power grid, and where Kenya Power installed a stand-alone hybrid mini-grid. Based on field observations, power generation data analysis, evaluation of the potential energy resources and simulations, this research intends to evaluate the performance of the Habaswein mini-grid and optimize the existing hybrid generation system to enhance its reliability and reduce the operation costs. The result will be a suggestion of how Kenyan rural areas could be sustainably electrified by using renewable energy based off-grid power stations. It will contribute to bridge the current research gap in this area, and it will be a vital tool to researchers, implementers and the policy makers in energy sector.
Characterisation of Ground Thermal and Thermo-Mechanical Behaviour for Shallow Geothermal Energy Applications
Authors: Vieira Ana , Alberdi-Pagola Maria , Christodoulides Paul , Javed Saqib , Loveridge Fleur , Nguyen Frederic , Cecinato Francesco , Maranha João , Florides Georgios , Prodan Iulia , Van Lysebetten Gust , Ramalho Elsa , Salciarini Diana , Georgiev Aleksandar , Rosin-Paumier Sandrine , Popov Rumen , Lenart Stanislav , Erbs Poulsen Søren , Radioti Georgia
Published: December 2017

Increasing use of the ground as a thermal reservoir is expected in the near future. Shallow geothermal energy (SGE) systems have proved to be sustainable alternative solutions for buildings and infrastructure conditioning in many areas across the globe in the past decades. Recently novel solutions, including energy geostructures, where SGE systems are coupled with foundation heat exchangers, have also been developed. The performance of these systems is dependent on a series of factors, among which the thermal properties of the soil play a major role. The purpose of this paper is to present, in an integrated manner, the main methods and procedures to assess ground thermal properties for SGE systems and to carry out a critical review of the methods. In particular, laboratory testing through either steady-state or transient methods are discussed and a new synthesis comparing results for different techniques is presented. In situ testing including all variations of the thermal response test is presented in detail, including a first comparison between new and traditional approaches. The issue of different scales between laboratory and in situ measurements is then analysed in detail. Finally, the thermo-hydro-mechanical behaviour of soil is introduced and discussed. These coupled processes are important for confirming the structural integrity of energy geostructures, but routine methods for parameter determination are still lacking.
Design and Experiment of Nonlinear Observer with Adaptive Gains for Battery State of Charge Estimation
Authors: Zhao Linhui , Ji Guohuang , Liu Zhiyuan
Published: December 2017

State of charge (SOC) is an important evaluation index for lithium-ion batteries (LIBs) in electric vehicles (EVs). This paper proposes a nonlinear observer with a new adaptive gain structure for SOC estimation based on a second-order RC model. It is able to dynamically adjust the gains and obtain a better balance between convergence speed and estimation accuracy with less computational time. A sufficient condition is derived to guarantee the uniform asymptotic stability of the observer, and its robustness with respect to disturbances and uncertainties is analyzed with the help of input-to-state stability (ISS) theory. A selection guide of the observer gains in practical application is presented. The estimation accuracy and convergence rate of the observer are evaluated and compared with those of extended Kalman filter (EKF) based on multi-temperature datasets from two different types of LIB cells. The robustness against different disturbances and uncertainties that may appear in a real vehicle is validated and discussed in detail. The experimental results show that the proposed observer is capable of achieving better performance with less computational time in comparison to EKF for different types of LIB cells under various working conditions. The observer is also capable of estimating SOC accurately for real life conditions according to the validation results of datasets from a battery management system (BMS) in an EV battery pack. Furthermore, the observer is simple enough, and is suitable for implementation on embedded hardware for LIB cells of EVs.
Segmentation of Residential Gas Consumers Using Clustering Analysis
Authors: Fernandes Marta , Viegas Joaquim , Vieira Susana , Sousa João
Published: December 2017

The growing environmental concerns and liberalization of energy markets have resulted in an increased competition between utilities and a strong focus on efficiency. To develop new energy efficiency measures and optimize operations, utilities seek new market-related insights and customer engagement strategies. This paper proposes a clustering-based methodology to define the segmentation of residential gas consumers. The segments of gas consumers are obtained through a detailed clustering analysis using smart metering data. Insights are derived from the segmentation, where the segments result from the clustering process and are characterized based on the consumption profiles, as well as according to information regarding consumers’ socio-economic and household key features. The study is based on a sample of approximately one thousand households over one year. The representative load profiles of consumers are essentially characterized by two evident consumption peaks, one in the morning and the other in the evening, and an off-peak consumption. Significant insights can be derived from this methodology regarding typical consumption curves of the different segments of consumers in the population. This knowledge can assist energy utilities and policy makers in the development of consumer engagement strategies, demand forecasting tools and in the design of more sophisticated tariff systems.
Power Characteristics Analysis of a Novel Double-Stator Magnetic Geared Permanent Magnet Generator
Authors: Salihu Mustafa Shehu , Misron Norhisam , Lutfi Othman Mohammad , Tsuyoshi Hanamoto
Published: December 2017

This paper presents the design, fabrication and experimental power analysis of a novel double-stator magnetic geared permanent magnet (DSMGPM) machine which comprises of a double-stator permanent-magnet (PM) machine integrated a with triple rotor magnetic gear. The proposed machine can upscale the low-speed rotating magnetic field of the prime PMs on the prime rotor by using the modulation effect produced from the pole-pieces to high-speed rotating magnetic field from the field PMs. The low-speed prime rotor can also increase the speed of the field PM rotor and excite the coil windings to induce an electromotive force (EMF) resulting in electrical power. Thus, the machine is proposed for power generation in low-speed renewable energy applications such as wind turbines and tidal power generators. The proposed machine topology is presented and discussed while the performance power characteristics are evaluated experimentally. A prototype is fabricated and the measured results are in good agreement with the calculated results, therefore validating the proposed magnetic geared machine design.
A Virtual Synchronous Generator Based Hierarchical Control Scheme of Distributed Generation Systems
Authors: Yao Gang , Lu Zhichong , Wang Yide , Benbouzid Mohamed , Moreau Luc
Published: December 2017

Sustainable energy-based generation systems, such as photovoltaic and wind turbine generation systems, normally adopt inverters to connect to the grid. These power electronic interfaces possess the characteristics of small inertia and small output impedance, which create difficulties to stabilize the voltage and frequency of a distributed power source. To deal with this problem, a Virtual Synchronous Generator (VSG)-based inverter control method is presented in this paper by introducing virtual inertia and damping coefficient into the control loop to emulate the dynamic behavior of a traditional synchronous generator. Based on this VSG control method, a three-layer hierarchical control scheme is further proposed to increase the control accuracy of the voltage and frequency in a VSG-based distributed generation system with parallel inverters. The principle of the VSG control method, the system stability analysis, the design process of the hierarchical control structure, and the frequency/voltage secondary regulation processes are all specified in this paper. Finally, some numerical simulations are carried out and the effectiveness of proposed control scheme is verified by the simulation results analysis.
Investigation of the Ampacity of a Prefabricated Straight-Through Joint of High Voltage Cable
Authors: Wang Pengyu , Liu Gang , Ma Hui , Liu Yigang , Xu Tao
Published: December 2017

This paper presents a theoretical and experimental study on the ampacity of the prefabricated straight-through joint of a 110 kV high voltage cable. Thermal modelling revealed that the critical spot limiting the ampacity of this type of cable joint is located on its crosslinked polyethylene (XLPE) insulation section. The axial distribution of the thermal field in this type of cable joint was also determined. An algorithm for assessing ampacity in this type of cable joint was developed. Experiments were conducted on a real cable system with a prefabricated straight-through joint under different loading conditions. The experiments show a good agreement with the thermal modelling results.
Coordinated Control of a Wind-Methanol-Fuel Cell System with Hydrogen Storage
Authors: Yuan Tiejiang , Duan Qingxi , Chen Xiangping , Yuan Xufeng , Cao Wenping , Hu Juan , Zhu Quanmin
Published: December 2017

This paper presents a wind-methanol-fuel cell system with hydrogen storage. It can manage various energy flow to provide stable wind power supply, produce constant methanol, and reduce CO2 emissions. Firstly, this study establishes the theoretical basis and formulation algorithms. And then, computational experiments are developed with MATLAB/Simulink (R2016a, MathWorks, Natick, MA, USA). Real data are used to fit the developed models in the study. From the test results, the developed system can generate maximum electricity whilst maintaining a stable production of methanol with the aid of a hybrid energy storage system (HESS). A sophisticated control scheme is also developed to coordinate these actions to achieve satisfactory system performance.
Forest Site Classification in the Southern Andean Region of Ecuador: A Case Study of Pine Plantations to Collect a Base of Soil Attributes
Authors: Quichimbo Pablo , Jiménez Leticia , Veintimilla Darío , Tischer Alexander , Günter Sven , Mosandl Reinhard , Hamer Ute
Published: December 2017

Forest site classification adapted to the respective site conditions is one prerequisite for sustainable silviculture. This work aims to initiate the forest site classification for pine plantations in the southern Andean region of Ecuador. Forest productivity, estimated by the dominant height of 20-year-old trees (DH20), was related to data from climate, topography, and soil using 23 plots installed in pine plantations in the province of Loja. Forest site productivity was classified as: low (class C: 13.4 m), middle (class B: 16.6 m), and high (Class A: 22.3 m). Strong determinants to differentiate the forest site classes were: the short to medium term available Ca and K stocks (organic layer + mineral soil standardized to a depth of 60 cm), soil acidity, the C:N ratio, clay and sand content, forest floor thickness, altitude, and slope. The lowest forest productivity (Class C) is mainly associated with the lowest short to medium term available K and Ca stocks. Whereas, in site classes with the highest forest productivity, pines could benefit from a more active microbial community releasing N and P, since the soil pH was about 1 unit less acidic. This is supported by the lowest forest floor thickness and the narrowest C:N ratio.
Physical Conditions Regulate the Fungal to Bacterial Ratios of a Tropical Suspended Soil
Authors: Donald Julian , Bonnett Sam , Cutler Michael , Majalap Noreen , Maxfield Pete , Ellwood M. D. Farnon
Published: December 2017

As a source of ‘suspended soils’, epiphytes contribute large amounts of organic matter to the canopy of tropical rain forests. Microbes associated with epiphytes are responsible for much of the nutrient cycling taking place in rain forest canopies. However, soils suspended far above the ground in living organisms differ from soil on the forest floor, and traditional predictors of soil microbial community composition and functioning (nutrient availability and the activity of soil organisms) are likely to be less important. We conducted an experiment in the rain forest biome at the Eden Project in the U.K. to explore how biotic and abiotic conditions determine microbial community composition and functioning in a suspended soil. To simulate their natural epiphytic lifestyle, bird’s nest ferns (Asplenium nidus) were placed on a custom-built canopy platform suspended 8 m above the ground. Ammonium nitrate and earthworm treatments were applied to ferns in a factorial design. Extracellular enzyme activity and Phospholipid Fatty Acid (PLFA) profiles were determined at zero, three and six months. We observed no significant differences in either enzyme activity or PLFA profiles between any of the treatments. Instead, we observed decreases in β-glucosidase and N-acetyl-glucosaminidase activity, and an increase in phenol oxidase activity across all treatments and controls over time. An increase in the relative abundance of fungi during the experiment meant that the microbial communities in the Eden Project ferns after six months were comparable with ferns sampled from primary tropical rain forest in Borneo.