Search results for: interference limited
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 4676

Search results for: interference limited

1886 Biodiversity Interactions Between C3 and C4 Plants under Agroforestry Cropping System

Authors: Ezzat Abd El Lateef

Abstract:

Agroforestry means combining the management of trees with productive agricultural activities, especially in semiarid regions where crop yield increases are limited in agroforestry systems due to the fertility and microclimate improvements and the large competitive effect of trees with crops for water and nutrients, in order to assess the effect of agroforestry of some field crops with citrus trees as an approach to establish biodiversity in fruit tree plantations. Three field crops, i.e., maize, soybean and sunflower, were inter-planted with seedless orange trees (4*4 m) or were planted as solid plantings. The results for the trees indicated a larger fruit yield was obtained when soybean and sunflowers were interplant with citrus. Statistically significant effects (P<0.05) were found for maize grain and biological yields, with increased yields when grown as solid planting. There were no differences in the yields of soya bean and sunflower, where the yields were very similar between the two cropping systems. It is evident from the trials that agroforestry is an efficient concept to increase biodiversity through the interaction of trees with the interplant field crop species. Maize, unlike the other crops, was more sensitive to shade conditions under agroforestry practice and not preferred in the biodiversity system. The potential of agroforestry to improve or increase biodiversity is efficient as the understorey crops are usually C4 species, and the overstorey trees are invariably C3 species in agroforestry. Improvement in interplant species is most likely if the understorey crop is a C3 species, which are usually light saturated in the open, and partial shade may have little effect on assimilation or by a concurrent reduction in transpiration. It could be concluded that agroforestry is an efficient concept to increase biodiversity through the interaction of trees with the interplant field crop species. Some field crops could be employed successfully, like soybean or sunflowers, while others like maize are sensitive to incorporate in agroforestry system.

Keywords: agroforestry, field crops, C3 and C4 plants, yield

Procedia PDF Downloads 177
1885 Study on the Stages of Knowledge Flow in Central Libraries of Tehran Universities by the Pattern of American Productivity & Quality Center

Authors: Amir Reza Asnafi, Ehsan Tajabadi, Mohsen Hajizeinolabedini

Abstract:

The purpose of this study is to identify the concept of knowledge flow in central libraries of Tehran universities in by the pattern of American Productivity & Quality Center (APQC). The present study is an applied and descriptive survey in terms of its purpose and the methodology used. In this study, APQC framework was used for data collection. The study population is managers and supervisors of central libraries’ departments of public universities of Tehran belonging to the Ministry of Science, Research and Technology. These libraries include: Central Libraries of Al-Zahra University, Amir Kabir, Tarbiat Modarres, Tehran, Khajeh Nasir Toosi University of Technology, Shahed, Sharif, Shahid Beheshti, Allameh Tabataba'i University, Iran University of Science and Technology. Due to the limited number of members of the community, sampling was not performed and the census was conducted instead. The study of knowledge flow in central libraries of public universities in Tehran showed that in seven dimensions of knowledge flow of APQC, these libraries are far from desirable level and to achieve the ideal point, many activities in the field of knowledge flow need to be made, therefore suggestions were made in this study to reach the desired level. One Sample t Test in this research showed that these libraries are at a poor level in terms of these factors: in the dimensions of creation, identification and use of knowledge at a medium level and in the aspects of knowledge acquisition, review, sharing and access and also Manova test or Multivariable Analyze of Variance proved that there was no significant difference between the dimensions of knowledge flow between these libraries and the status of the knowledge flow in these libraries is at the same level as well. Except for the knowledge creation aspect that is slightly different in this regard that was mentioned before.

Keywords: knowledge flow, knowledge management, APQC, Tehran’s academic university libraries

Procedia PDF Downloads 149
1884 Risk Management Practices In The Construction Industry In Malawi

Authors: Taonga Temwani Chibaka

Abstract:

This qualitative research study was conducted to identify the common risk factors that affect the construction industry in Malawi in the building and infrastructure (civil works) projects. The study then evaluates the possible risk responses that are done to mitigate the various risk factors that were identified. I addition the research also established the barriers to risk management implementation with lastly mapping out as where the identified risk factors fall on which stage of the project and then also map out the knowledge areas that need to be worked on the cases on Malawian construction industry in order to mitigate most of the identified risk factors. The study involved the interviewing the professionals from the construction industry in Malawi where insights and ideas were collected, analysed and interpreted. The key study findings show that risks related to clients group are perceived as most critical followed by the contractor related, consultant related and then external group related factors respectively where preventive measures are the most applied risk response technique where the aim to avoid most of the risk factors from happening. Most of the risk factors identified were internal risks and in managerial category which suggested that risk planning was to be emphasized at pre-contract stage to minimize these risks since a bigger percentage of the risk factors were mapped out at implementation stage. Furthermore, barriers to risk management were identified and the key barriers were lack of awareness; lack of knowledge; lack of formal policies in place; regarded as costly and limited time which resulted in proposing that regulating authorities to purposefully introduce intense training on risk management to make known of this new knowledge area. The study then recommends that organisation should formally implement risk management where policies should be introduced to enforce all parties to undertake this. Risk planning was regarded as paramount and this to be done from pre-contract phase so as to mitigate 80% of the risk factors. Finally, training should be done on all project management knowledge areas.

Keywords: risk management, risk factors, risks, malawi

Procedia PDF Downloads 304
1883 Study of the Hydrochemical Composition of Canal, Collector-Drainage and Ground Waters of Kura-Araz Plain and Modeling by GIS Method

Authors: Gurbanova Lamiya

Abstract:

The Republic of Azerbaijan is considered a region with limited water resources, as up to 70% of surface water is formed outside the country's borders, and most of its territory is an arid (dry) climate zone. It is located at the lower limit of transboundary flows, which is the weakest source of natural water resources in the South Caucasus. It is essential to correctly assess the quality of natural, collector-drainage and groundwater of the area and their suitability for irrigation in order to properly carry out land reclamation measures, provide the normal water-salt regime, and prevent repeated salinization. Through the 141-km-long main Mil-Mugan collector, groundwater, household waste, and floodwaters generated during floods and landslides are poured into the Caspian Sea. The hydrochemical composition of the samples taken from the Sabir irrigation canal passing through the center of the Kura-Araz plain, the Main Mil-Mugan Collector, and the groundwater of the region, which we chose as our research object, were studied and the obtained results were compared by periods. A model is proposed that allows for a complete visualization of the primary materials collected for the study area. The practical use of the established digital model provides all possibilities. The practical use of the established digital model provides all possibilities. An extensive database was created with the ArcGis 10.8 package, using publicly available LandSat satellite images as primary data in addition to ground surveys to build the model. The principles of the construction of the geographic information system of modern GIS technology were developed, the boundary and initial condition of the research area were evaluated, and forecasts and recommendations were given.

Keywords: irrigation channel, groundwater, collector, meliorative measures

Procedia PDF Downloads 65
1882 Unprecedented Bioactive Naturally-occurring Compounds from the Rare and Endangered Plants Endemic to China

Authors: Jin-Feng Hu

Abstract:

Over the past decades, the global biodiversity has continued to decline. The threats to the terrestrial plant species have increased under anthropogenic activities and other massive ecological change impacts. The situation is much more serious in China, the third richest countries regarding plant biodiversity in the world. It was not until 1992 that the first volume of the China Plant Red Data Book was published. Nowadays, a significant number of Chinese endemic plants have been threatened (The IUCN Red List). Nevertheless, plant-originated natural products (NPs) have continued to play a crucial role in the drug discovery and development process. The opportunity for identifying new chemical entities for emerging and malignant diseases depends on a diversity of drug-producing species. Several statistical surveys unveiled that the rare and endangered plants (REPs) have proven to be better sources for drug discovery than other botanic sources. The identification of bioactive NPs from REPs reveals the importance of conservation efforts in preventing species diversity loss and addressing human diseases at the same time. Thus, there is an urgent need to investigate these fragile REPs. Since 2013, our group has initially launched a special program to systematically identify bioactive/novel NPs from REPs native to China. The selected plant species were generally collected from the remote Mountain areas, and have never been chemically or pharmacologically investigated. Due to the difficult collection of the mass-limited samples of REPs, studies on the secondary metabolites of REPs-associated endophytes would provide a promising alternative potential solution. This presentation details the achievements that related to a series of “Phytochemical and biological studies on rare and endangered plants endemic to China”.

Keywords: bioactive naturally-occrring compounds, rare and endengered plants (REPs), plant endophytes, drug discovery

Procedia PDF Downloads 23
1881 Sexual Health in the Over Forty-Fives: A Cross-Europe Project

Authors: Tess Hartland, Moitree Banerjee, Sue Churchill, Antonina Pereira, Ian Tyndall, Ruth Lowry

Abstract:

Background: Sexual health services and policies for middle-aged and older adults are underdeveloped, while global sexually transmitted infections in this age group are on the rise. The Interreg cross-Europe Sexual Health In Over 45s (SHIFT) project aims to increase participation in sexual health services and improve sexual health and wellbeing in people aged over 45, with an additional focus on disadvantaged groups. Methods: A two-pronged mixed-methodology is being used to develop a model for good service provision in sexual health for over 45s. (1) Following PRISMA-ScR guidelines, a scoping review is being conducted, using the databases PsychINFO, Web of Science, ERIC and PubMed. A key search strategy using terms around sexual health, good practice, over 45s and disadvantaged groups. The initial search for literature yielded 7914 results. (2) Surveys (n=1000) based on the Theory of Planned Behaviour are being administered across the UK, Belgium and Netherlands to explore current sexual health knowledge, awareness and attitudes. Expected results: It is expected that sexual health needs and potential gaps in service provision will be identified in order to inform good practice for sexual health services for the target population. Results of the scoping review are being analysed, while focus group and survey data is being gathered. Preliminary analysis of the survey data highlights barriers to access such as limited risk awareness and stigma. All data analysis will be completed by the time of the conference. Discussion: Findings will inform the development of a model to improve sexual health and wellbeing for among over 45s, a population which is often missed in sexual health policy improvement.

Keywords: adult health, disease prevention, health promotion, over 45s, sexual health

Procedia PDF Downloads 123
1880 Clustering-Based Threshold Model for Condition Rating of Concrete Bridge Decks

Authors: M. Alsharqawi, T. Zayed, S. Abu Dabous

Abstract:

To ensure safety and serviceability of bridge infrastructure, accurate condition assessment and rating methods are needed to provide basis for bridge Maintenance, Repair and Replacement (MRR) decisions. In North America, the common practices to assess condition of bridges are through visual inspection. These practices are limited to detect surface defects and external flaws. Further, the thresholds that define the severity of bridge deterioration are selected arbitrarily. The current research discusses the main deteriorations and defects identified during visual inspection and Non-Destructive Evaluation (NDE). NDE techniques are becoming popular in augmenting the visual examination during inspection to detect subsurface defects. Quality inspection data and accurate condition assessment and rating are the basis for determining appropriate MRR decisions. Thus, in this paper, a novel method for bridge condition assessment using the Quality Function Deployment (QFD) theory is utilized. The QFD model is designed to provide an integrated condition by evaluating both the surface and subsurface defects for concrete bridges. Moreover, an integrated condition rating index with four thresholds is developed based on the QFD condition assessment model and using K-means clustering technique. Twenty case studies are analyzed by applying the QFD model and implementing the developed rating index. The results from the analyzed case studies show that the proposed threshold model produces robust MRR recommendations consistent with decisions and recommendations made by bridge managers on these projects. The proposed method is expected to advance the state of the art of bridges condition assessment and rating.

Keywords: concrete bridge decks, condition assessment and rating, quality function deployment, k-means clustering technique

Procedia PDF Downloads 217
1879 Estimate Robert Gordon University's Scope Three Emissions by Nearest Neighbor Analysis

Authors: Nayak Amar, Turner Naomi, Gobina Edward

Abstract:

The Scottish Higher Education Institutes must report their scope 1 & 2 emissions, whereas reporting scope 3 is optional. Scope 3 is indirect emissions which embodies a significant component of total carbon footprint and therefore it is important to record, measure and report it accurately. Robert Gordon University (RGU) reported only business travel, grid transmission and distribution, water supply and transport, and recycling scope 3 emissions. This study estimates the RGUs total scope 3 emissions by comparing it with a similar HEI in scale. The scope 3 emission reporting of sixteen Scottish HEI was studied. Glasgow Caledonian University was identified as the nearest neighbour by comparing its students' full time equivalent, staff full time equivalent, research-teaching split, budget, and foundation year. Apart from the peer, data was also collected from the Higher Education Statistics Agency database. RGU reported emissions from business travel, grid transmission and distribution, water supply, and transport and recycling. This study estimated RGUs scope 3 emissions from procurement, student-staff commute, and international student trip. The result showed that RGU covered only 11% of the scope 3 emissions. The major contributor to scope 3 emissions were procurement (48%), student commute (21%), international student trip (16%), and staff commute (4%). The estimated scope 3 emission was more than 14 times the reported emissions. This study has shown the relative importance of each scope 3 emissions source, which gives a guideline for the HEIs, on where to focus their attention to capture maximum scope 3 emissions. Moreover, it has demonstrated that it is possible to estimate the scope 3 emissions with limited data.

Keywords: HEI, university, emission calculations, scope 3 emissions, emissions reporting

Procedia PDF Downloads 93
1878 Effectiveness of Computer Video Games on the Levels of Anxiety of Children Scheduled for Tooth Extraction

Authors: Marji Umil, Miane Karyle Urolaza, Ian Winston Dale Uy, John Charle Magne Valdez, Karen Elizabeth Valdez, Ervin Charles Valencia, Cheryleen Tan-Chua

Abstract:

Objective: Distraction techniques can be successful in reducing the anxiety of children during medical procedures. Dental procedures, in particular, are associated with dental anxiety which has been identified as a significant and common problem in children, however, only limited studies were conducted to address such problem. Thus, this study determined the effectiveness of computer video games on the levels of anxiety of children between 5-12 years old scheduled for tooth extraction. Methods: A pre-test post-test quasi-experimental study was conducted involving 30 randomly-assigned subjects, 15 in the experimental and 15 in the control. Subjects in the experimental group played computer video games for a maximum of 15 minutes, however, no intervention was done on the control. The modified Yale Pre-operative Anxiety Scale (m-YPAS) with a Cronbach’s alpha of 0.9 was used to assess anxiety at two different points: upon arrival in the clinic (pre-test anxiety) and 15 minutes after the first measurement (post-test anxiety). Paired t-test and ANCOVA were used to analyze the gathered data. Results: Results showed that there is a significant difference between the pre-test and post-test anxiety scores of the control group (p=0.0002) which indicates an increased anxiety. A significant difference was also noted between the pre-test and post-test anxiety scores of the experimental group (p=0.0002) which indicates decreased anxiety. Comparatively, the experimental group showed lower anxiety score (p=<0.0001) than the control. Conclusion: The use of computer video games is effective in reducing the pre-operative anxiety among children and can be an alternative non-pharmacological management in giving pre-operative care.

Keywords: play therapy, preoperative anxiety, tooth extraction, video games

Procedia PDF Downloads 438
1877 Gnss Aided Photogrammetry for Digital Mapping

Authors: Muhammad Usman Akram

Abstract:

This research work based on GNSS-Aided Photogrammetry for Digital Mapping. It focuses on topographic survey of an area or site which is to be used in future Planning & development (P&D) or can be used for further, examination, exploration, research and inspection. Survey and Mapping in hard-to-access and hazardous areas are very difficult by using traditional techniques and methodologies; as well it is time consuming, labor intensive and has less precision with limited data. In comparison with the advance techniques it is saving with less manpower and provides more precise output with a wide variety of multiple data sets. In this experimentation, Aerial Photogrammetry technique is used where an UAV flies over an area and captures geocoded images and makes a Three-Dimensional Model (3-D Model), UAV operates on a user specified path or area with various parameters; Flight altitude, Ground sampling distance (GSD), Image overlapping, Camera angle etc. For ground controlling, a network of points on the ground would be observed as a Ground Control point (GCP) using Differential Global Positioning System (DGPS) in PPK or RTK mode. Furthermore, that raw data collected by UAV and DGPS will be processed in various Digital image processing programs and Computer Aided Design software. From which as an output we obtain Points Dense Cloud, Digital Elevation Model (DEM) and Ortho-photo. The imagery is converted into geospatial data by digitizing over Ortho-photo, DEM is further converted into Digital Terrain Model (DTM) for contour generation or digital surface. As a result, we get Digital Map of area to be surveyed. In conclusion, we compared processed data with exact measurements taken on site. The error will be accepted if the amount of error is not breached from survey accuracy limits set by concerned institutions.

Keywords: photogrammetry, post processing kinematics, real time kinematics, manual data inquiry

Procedia PDF Downloads 12
1876 The Biopsychosocial Effects of Amputation on Transtibial Amputees in Kwazulu-Natal

Authors: Riyona Chetty, Raisuyah Bhagwan, Nalini Govender

Abstract:

Background: A myriad of physical, psychosocial, and environmental sequelae are associated with limb loss. However, there is a paucity of empirical South African data, which focuses on these sequelae, how they interface with the amputee’s quality of life as well as the challenges they experience following amputation. Objective: This study sought to explore the biopsychosocial effects of amputation and how amputation affected the quality of life of transtibial amputees. Setting: Participants were recruited from a medical facility, under the KwaZulu-Natal Department of Health in South Africa. Methods: A qualitative approach guided this study. Data was collected using one-on-one interviews with 14 unilateral transtibial amputees. Data was analysed thematically. Results: Five broad themes emerged from the inquiry, which captured amputees’ experiences of phantom limb pain, body image disturbances, and their challenges related to adapting to daily activities. Participants also expressed the salience of familial support as well as the importance of psychological interventions to cope. Conclusion: The findings suggested that support networks and professional psychological intervention are imperative in facilitating successful adjustment to the amputation experience. Raising awareness of limb loss in both, rural and urban settings may help reduce the stigma attached to it. Contribution: Quality of life comprises several domains, namely physical, psychological, environmental, and social albeit limited local and international data exists regarding the environmental and social effects. This study brought to the fore the positive and negative effects of amputation in each domain, as well as various strategies that facilitate successful adjustment to amputation.

Keywords: amputation, quality of life, biopsychosocial, phantom limb pain, body image, support

Procedia PDF Downloads 46
1875 High-Resolution Flood Hazard Mapping Using Two-Dimensional Hydrodynamic Model Anuga: Case Study of Jakarta, Indonesia

Authors: Hengki Eko Putra, Dennish Ari Putro, Tri Wahyu Hadi, Edi Riawan, Junnaedhi Dewa Gede, Aditia Rojali, Fariza Dian Prasetyo, Yudhistira Satya Pribadi, Dita Fatria Andarini, Mila Khaerunisa, Raditya Hanung Prakoswa

Abstract:

Catastrophe risk management can only be done if we are able to calculate the exposed risks. Jakarta is an important city economically, socially, and politically and in the same time exposed to severe floods. On the other hand, flood risk calculation is still very limited in the area. This study has calculated the risk of flooding for Jakarta using 2-Dimensional Model ANUGA. 2-Dimensional model ANUGA and 1-Dimensional Model HEC-RAS are used to calculate the risk of flooding from 13 major rivers in Jakarta. ANUGA can simulate physical and dynamical processes between the streamflow against river geometry and land cover to produce a 1-meter resolution inundation map. The value of streamflow as an input for the model obtained from hydrological analysis on rainfall data using hydrologic model HEC-HMS. The probabilistic streamflow derived from probabilistic rainfall using statistical distribution Log-Pearson III, Normal and Gumbel, through compatibility test using Chi Square and Smirnov-Kolmogorov. Flood event on 2007 is used as a comparison to evaluate the accuracy of model output. Property damage estimations were calculated based on flood depth for 1, 5, 10, 25, 50, and 100 years return period against housing value data from the BPS-Statistics Indonesia, Centre for Research and Development of Housing and Settlements, Ministry of Public Work Indonesia. The vulnerability factor was derived from flood insurance claim. Jakarta's flood loss estimation for the return period of 1, 5, 10, 25, 50, and 100 years, respectively are Rp 1.30 t; Rp 16.18 t; Rp 16.85 t; Rp 21.21 t; Rp 24.32 t; and Rp 24.67 t of the total value of building Rp 434.43 t.

Keywords: 2D hydrodynamic model, ANUGA, flood, flood modeling

Procedia PDF Downloads 268
1874 Self-Assembly of TaC@Ta Core-Shell-Like Nanocomposite Film via Solid-State Dewetting: Toward Superior Wear and Corrosion Resistance

Authors: Ping Ren, Mao Wen, Kan Zhang, Weitao Zheng

Abstract:

The improvement of comprehensive properties including hardness, toughness, wear, and corrosion resistance in the transition metal carbides/nitrides TMCN films, especially avoiding the trade-off between hardness and toughness, is strongly required to adapt to various applications. Although incorporating ductile metal DM phase into the TMCN via thermally-induced phase separation has been emerged as an effective approach to toughen TMCN-based films, the DM is just limited to some soft ductile metal (i.e. Cu, Ag, Au immiscibility with the TMCN. Moreover, hardness is highly sensitive to soft DM content and can be significantly worsened. Hence, a novel preparation method should be attempted to broaden the DM selection and assemble much more ordered nanocomposite structure for improving the comprehensive properties. Here, we provide a new strategy, by activating solid-state dewetting during layered deposition, to accomplish the self-assembly of ordered TaC@Ta core-shell-like nanocomposite film consisting of TaC nanocrystalline encapsulated with thin pseudocrystal Ta tissue. That results in the superhard (~45.1 GPa) dominated by Orowan strengthening mechanism and high toughness attributed to indenter-induced phase transformation from the pseudocrystal to body-centered cubic Ta, together with the drastically enhanced wear and corrosion resistance. Furthermore, very thin pseudocrystal Ta encapsulated layer (~1.5 nm) in the TaC@Ta core-shell-like structure helps for promoting the formation of lubricious TaOₓ Magnéli phase during sliding, thereby further dropping the coefficient of friction. Apparently, solid-state dewetting may provide a new route to construct ordered TMC(N)@TM core-shell-like nanocomposite capable of combining superhard, high toughness, low friction, superior wear with corrosion resistance.

Keywords: corrosion, nanocomposite film, solid-state dewetting, tribology

Procedia PDF Downloads 131
1873 The Cost-Effectiveness of High-Volume Hospital’s Surgical Care for Pancreatic Cancer: Economic Evidence Reviewed

Authors: Shannon Hearney, Jeffrey Hoch

Abstract:

Pancreatic cancer is a notoriously costly and deadly form of cancer. Many types of treatment centers exist for patients to seek care from, including high-volume centers which have shown promise to provide the highest quality of care. While it may be true that this type of center provides the best care it is unclear if that care is cost-effective. Studies in the US have confirmed that high-volume hospitals do provide higher quality of care but have shown inconsistencies in the cost-effectiveness of that care. Other studies, like those from Finland have shown that high-volume centers had lower mortality and lower costs than low-volume centers. This paper thus seeks to review the current scientific literature to better understand if high-volume centers are cost-effective in delivering care in both a European setting and in the US. A review of major reference databases such as Medline, Embase and PubMed will be conducted for cost-effectiveness studies on the surgical treatment of pancreatic cancer at high-volume centers. Possible MeSH terms to be included, but not limited to, are: “pancreatic cancer”, “cost analysis”, “cost-effectiveness”, “economic evaluation”, “pancreatic neoplasms”, “surgical”, and “high-volume”. Studies must also have been available in the English language. This review will encompass European scientific literature, as well as those in the US. Based on our preliminary findings, we anticipate high-volume hospitals to provide better care at greater costs. We anticipate that high-volume hospitals may be cost-effective in different contexts depending on the national structure of a healthcare system. Countries with more centralized and socialized healthcare may yield results that are more cost-effective. High-volume centers may differ in their cost-effectiveness of the surgical care of pancreatic cancer internationally especially when comparing those in the United States to others throughout Europe.

Keywords: cost-effectiveness analysis, economic evaluation, pancreatic cancer, scientific literature review

Procedia PDF Downloads 85
1872 Effect of Flour Concentration and Retrogradation Treatment on Physical Properties of Instant Sinlek Brown Rice

Authors: Supat Chaiyakul, Direk Sukkasem, Patnachapa Natthapanpaisith

Abstract:

Sinlek rice flour beverage or instant product is a dietary supplement for dysphagia, or difficulty swallowing. It is also consumed by individuals who need to consume supplements to maintain their calorific needs. This product provides protein, fat, iron, and a high concentration of carbohydrate from rice flour. However, the application of native flour is limited due to its high viscosity. Starch modification by controlling starch retrogradation was used in this study. The research studies the effects of rice flour concentration and retrogradation treatment on the physical properties of instant Sinlek brown rice. The native rice flour, gelatinized rice flour, and flour gels retrograded under 4 °C for 3 and 7 days were investigated. From the statistical results, significant differences between native and retrograded flour were observed. The concentration of rice flour was the main factor influencing the swelling power, solubility, and pasting properties. With the increase in rice flour content from 10 to 15%, swelling power, peak viscosity, trough, and final viscosity decreased; but, solubility, pasting temperature, peak time, breakdown, and setback increased. The peak time, pasting temperature, peak viscosity, trough, and final viscosity decreased as the storage period increased from 3 to 7 days. The retrograded rice flour powders had lower pasting temperature, peak viscosity, breakdown, and final viscosity than the gelatinized and native flour powders. Reduction of starch viscosity by gelatinization and controlling starch retrogradation could allow for increased quantities of rice flour in instant rice beverages. Also, the treatment could increase the energy and nutrient densities of rice beverages without affecting the viscosity of this product.

Keywords: instant rice, pasting properties, pregelatinization, retrogradation

Procedia PDF Downloads 232
1871 An Experiment Research on the Effect of Brain-Break in the Classroom on Elementary School Students’ Selective Attention

Authors: Hui Liu, Xiaozan Wang, Jiarong Zhong, Ziming Shao

Abstract:

Introduction: Related research shows that students don’t concentrate on teacher’s speaking in the classroom. The d2 attention test is a time-limited test about selective attention. The d2 attention test can be used to evaluate individual selective attention. Purpose: To use the d2 attention test tool to measure the difference between the attention level of the experimental class and the control class before and after Brain-Break and to explore the effect of Brain-Break in the classroom on students' selective attention. Methods: According to the principle of no difference in pre-test data, two classes in the fourth- grade of Shenzhen Longhua Central Primary School were selected. After 20 minutes of class in the third class in the morning and the third class in the afternoon, about 3-minute Brain-Break intervention was performed in the experimental class for 10 weeks. The normal class in the control class did not intervene. Before and after the experiment, the d2 attention test tool was used to test the attention level of the two-class students. The paired sample t-test and independent sample t-test in SPSS 23.0 was used to test the change in the attention level of the two-class classes around 10 weeks. This article only presents results with significant differences. Results: The independent sample t-test results showed that after ten-week of Brain-Break, the missed errors (E1 t = -2.165 p = 0.042), concentration performance (CP t = 1.866 p = 0.05), and the degree of omissions (Epercent t = -2.375 p = 0.029) in experimental class showed significant differences compared with control class. The students’ error level decreased and the concentration increased. Conclusions: Adding Brain-Break interventions in the classroom can effectively improve the attention level of fourth-grade primary school students to a certain extent, especially can improve the concentration of attention and decrease the error rate in the tasks. The new sport's learning model is worth promoting

Keywords: cultural class, micromotor, attention, D2 test

Procedia PDF Downloads 124
1870 Polymersomes in Drug Delivery: A Comparative Review with Liposomes and Micelles

Authors: Salma E. Ahmed

Abstract:

Since the mid 50’s, enormous attention has been paid towards nanocarriers and their applications in drug and gene delivery. Among these vesicles, liposomes and micelles have been heavily investigated due to their many advantages over other types. Liposomes, for instance, are mostly distinguished by their ability to encapsulate hydrophobic, hydrophilic and amphiphilic drugs. Micelles, on the other hand, are self-assembled shells of lipids, amphiphilic or oppositely charged block copolymers that, once exposed to aqueous media, can entrap hydrophobic agents, and possess prolonged circulation in the bloodstream. Both carriers are considered compatible and biodegradable. Nevertheless, they have limited stabilities, chemical versatilities, and drug encapsulation efficiencies. In order to overcome these downsides, strategies for optimizing a novel drug delivery system that has the architecture of liposomes and polymeric characteristics of micelles have been evolved. Polymersomes are vehicles with fluidic cores and hydrophobic shells that are protected and isolated from the aqueous media by the hydrated hydrophilic brushes which give the carrier its distinctive polymeric bilayer shape. Similar to liposomes, this merit enables the carrier to encapsulate a wide range of agents, despite their affinities and solubilities in water. Adding to this, the high molecular weight of the amphiphiles that build the body of the polymersomes increases their colloidal and chemical stabilities and reduces the permeability of the polymeric membranes, which makes the vesicles more protective to the encapsulated drug. These carriers can also be modified in ways that make them responsive when targeted or triggered, by manipulating their composition and attaching moieties and conjugates to the body of the carriers. These appealing characteristics, in addition to the ease of synthesis, gave the polymersomes greater potentials in the area of drug delivery. Thus, their design and characterization, in comparison with liposomes and micelles, are briefly reviewed in this work.

Keywords: controlled release, liposomes, micelles, polymersomes, targeting

Procedia PDF Downloads 191
1869 Development of Immuno-Modulators: Application of Molecular Dynamics Simulation

Authors: Ruqaiya Khalil, Saman Usmani, Zaheer Ul-Haq

Abstract:

The accurate characterization of ligand binding affinity is indispensable for designing molecules with optimized binding affinity. Computational tools help in many directions to predict quantitative correlations between protein-ligand structure and their binding affinities. Molecular dynamics (MD) simulation is a modern state-of-the-art technique to evaluate the underlying basis of ligand-protein interactions by characterizing dynamic and energetic properties during the event. Autoimmune diseases arise from an abnormal immune response of the body against own tissues. The current regimen for the described condition is limited to immune-modulators having compromised pharmacodynamics and pharmacokinetics profiles. One of the key player mediating immunity and tolerance, thus invoking autoimmunity is Interleukin-2; a cytokine influencing the growth of T cells. Molecular dynamics simulation techniques are applied to seek insight into the inhibitory mechanisms of newly synthesized compounds that manifested immunosuppressant potentials during in silico pipeline. In addition to estimation of free energies associated with ligand binding, MD simulation yielded us a great deal of information about ligand-macromolecule interactions to evaluate the pattern of interactions and the molecular basis of inhibition. The present study is a continuum of our efforts to identify interleukin-2 inhibitors of both natural and synthetic origin. Herein, we report molecular dynamics simulation studies of Interluekin-2 complexed with different antagonists previously reported by our group. The study of protein-ligand dynamics enabled us to gain a better understanding of the contribution of different active site residues in ligand binding. The results of the study will be used as the guide to rationalize the fragment based synthesis of drug-like interleukin-2 inhibitors as immune-modulators.

Keywords: immuno-modulators, MD simulation, protein-ligand interaction, structure-based drug design

Procedia PDF Downloads 249
1868 Swallowing Outcomes in Supraglottic Cancer Patients after Trans-Oral Robotic Surgery (TORS) Provided with Early Dysphagia Management Using Standardized Functional and Objective Measures

Authors: Hitesh Gupta, Surender Dabas

Abstract:

TORS is increasingly gaining widespread use and has been explored as minimally invasive surgery for the treatment of supraglottic cancer (SGC). Being a central critical role of Supraglottis in deglutition, swallowing outcomes post TORS remain a most important factor. Available published studies show inconsistent swallowing outcomes and are deficient in standardized outcome measures, description of swallowing recovery and rehabilitation. So, the objective of this study is to find out swallowing outcomes in SGC patients after TORS provided with early dysphagia management using standardized measures. Prospectively 16 patients were recruited in the study who underwent TORS for primary tumor of Supraglottis, involving one or more sub-sites or invading to sites other than Supraglottis at the BLK Super Specialty Hospital, New Delhi from March 2019 to June 2020. All patients were evaluated for dysphagia with subsequent swallowing rehabilitation on post operative day 3 in the hospital or at the time of discharge, whichever was earlier. Functional oral intake scale (FOIS) and penetration-aspiration score (PAS) were used as outcome measures to quantify swallowing recovery at one month and six month post operatively. Post TORS, patients achieved functional swallow in less than one month, where resection was limited to Supraglottis, while the recovery was delayed in patients with extended resection to tongue base or hypopharynx. Overall, out of Total 16 cases including all supraglottis sub-catagories, 13 (81%) could remove their NG tube (FOIS ≥5 and PAS=1 ) within 6 months. In which 8 cases(62%) achieved functional swallow in less than one month. Swallowing outcomes post TORS supraglottic laryngectomy are favorable if provided with early dysphagia management (or swallowing rehabilitation).

Keywords: dysphagia, supraglottic cancer, swallowing, TORS

Procedia PDF Downloads 100
1867 Character Strengths Use in the Autism Classroom: An Intervention over Six Weeks to Support Teachers, Teaching Assistants and Learners

Authors: Chantel Snyman, Chrizanne van Eeden, Marita Heyns

Abstract:

Autism spectrum disorder (ASD) is one of the most common disabilities in schools, with up to50% of children displaying behaviors that challenge, bringing about demanding teaching circumstances. The teachers and teaching assistants of such learners often experience a negative impact on their own quality of life. Research globally and in South Africa about the teachers of ASD learners and teaching interventions, especially positive psychology approaches aimed at supporting learners with ASD, is limited. The primary research aim of this study was to investigate the feasibility as well as the effect of a strength-based intervention for teachers on the behavior of their learners with ASD and on the wellbeing and self-efficacy of teachers and assistants over time. This quantitative study used a pre-experimental group design with a pre-test-post-test method for the proposed school-based intervention. Teachers and teaching assistants completed the Difficult Behavior Self-Efficacy Scale, the Mental Health Questionnaire, and the short Behaviors That Challenge Checklist for learners with ASD. The six-week intervention on character strengths was delivered by the researcher as part of Teacher Staff Development. Results were generally significant on a practical level (based on practical effect sizes), which indicate that the intervention had a visible effect on behaviors that challenge. Research scores over time suggested a positive effect of the intervention in the well-being of participants and an overall positive effect on behaviors that challenge of ASD learners. Results showed that the character strengths intervention shows promise as a simple but effective intervention for teachers and teaching assistants, with positive effects for learners and teaching staff in the ASD classroom. It is recommended that this intervention should be repeated over a longer period of time and with a larger sample to determine its validity.

Keywords: autism spectrum disorder (ASD), behavior that challenge, character strengths, disabilities, self-efficacy, teachers, teaching assistants, well-being

Procedia PDF Downloads 97
1866 Building Information Management Advantages, Adaptation, and Challenges of Implementation in Kabul Metropolitan Area

Authors: Mohammad Rahim Rahimi, Yuji Hoshino

Abstract:

Building Information Management (BIM) at recent years has widespread consideration on the Architecture, Engineering and Construction (AEC). BIM has been bringing innovation in AEC industry and has the ability to improve the construction industry with high quality, reduction time and budget of project. Meanwhile, BIM support model and process in AEC industry, the process include the project time cycle, estimating, delivery and generally the way of management of project but not limited to those. This research carried the BIM advantages, adaptation and challenges of implementation in Kabul region. Capital Region Independence Development Authority (CRIDA) have responsibilities to implement the development projects in Kabul region. The method of study were considers on advantages and reasons of BIM performance in Afghanistan based on online survey and data. Besides that, five projects were studied, the reason of consideration were many times design revises and changes. Although, most of the projects had problems regard to designing and implementation stage, hence in canal project was discussed in detail with the main reason of problems. Which were many time changes and revises due to the lack of information, planning, and management. In addition, two projects based on BIM utilization in Japan were also discussed. The Shinsuizenji Station and Oita River dam projects. Those are implemented and implementing consequently according to the BIM requirements. The investigation focused on BIM usage, project implementation process. Eventually, the projects were the comparison with CRIDA and BIM utilization in Japan. The comparison will focus on the using of the model and the way of solving the problems based upon on the BIM. In conclusion, that BIM had the capacity to prevent many times design changes and revises. On behalf of achieving those objectives are required to focus on data management and sharing, BIM training and using new technology.

Keywords: construction information management, implementation and adaptation of BIM, project management, developing countries

Procedia PDF Downloads 122
1865 Changing Subjective Well-Being and Social Trust in China: 2010-2020

Authors: Mengdie Ruan

Abstract:

The authors investigate how subjective well-being (SWB) and social trust changed in China over the period 2010–2020 by relying on data from six rounds of the China Family Panel Studies (CFPS), then re-examine Easterlin’s hypothesis for China, with a more focus on the role of social trust and estimate income-compensating differentials for social trust. They find that the evolution of well-being is not sensitive to the measures of well-being one uses. Specifically, self-reported life satisfaction scores and hedonic happiness scores experienced a significant increase across all income groups from 2010 to 2020. Social trust seems to have increased based on CFPS in China for all socioeconomic classes in recent years, and male, urban resident individuals with higher income have a higher social trust at a given point in time and over time. However, when we use an alternative measure of social trust, out-group trust, which is a more valid measure of generalized trust and represents “most people”, social trust in China literally declines, and the level is extremely low. In addition, this paper also suggests that in the typical query on social trust, the term "most people" mostly denotes in-groups in China, which contrasts sharply with most Western countries where it predominantly connotes out-groups. Individual fixed effects analysis of well-being that controls for time-invariant variables reveals social trust and relative social status are important correlates of life satisfaction and happiness, whereas absolute income plays a limited role in boosting an individual’s well-being. The income-equivalent value for social capital is approximately tripling of income. It has been found that women, urban and coastal residents, and people with higher income, young people, those with high education care more about social trust in China, irrespective of measures on SWB. Policy aiming at preserving and enhancing SWB should focus on social capital besides economic growth.

Keywords: subjective well-being, life satisfaction, happiness, social trust, China

Procedia PDF Downloads 68
1864 The Revenue Management Implementation and Its Complexity in the Airline Industry: An Empirical Study on the Egyptian Airline Industry

Authors: Amr Sultan, Sara Elgazzar, Breksal Elmiligy

Abstract:

The airline industry nowadays is becoming a more growing industry facing a severe competition. It is an influential issue in this context to utilize revenue management (RM) concept and practice in order to develop the pricing strategy. There is an unfathomable necessity for RM to assist the airlines and their associates to disparage the cost and recuperate their revenue, which in turn will boost the airline industry performance. The complexity of RM imposes enormous challenges on the airline industry. Several studies have been proposed on the RM adaptation in airlines industry while there is a limited availability of implementing RM and its complexity in the developing countries such as Egypt. This research represents a research schema about the implementation of the RM to the Egyptian airline industry. The research aims at investigating and demonstrating the complexities face implementing RM in the airline industry, up on which the research provides a comprehensive understanding of how to overcome these complexities while adapting RM in the Egyptian airline industry. An empirical study was conducted on the Egyptian airline sector based on a sample of four airlines (Egyptair, Britishair, KLM, and Lufthansa). The empirical study was conducted using a mix of qualitative and quantitative approaches. First, in-depth interviews were carried out to analyze the Egyptian airline sector status and the main challenges faced by the airlines. Then, a structured survey on the three different parties of airline industry; airlines, airfreight forwarders, and passengers were conducted in order to investigate the main complexity factors from different parties' points of view. Finally, a focus group was conducted to develop a best practice framework to overcome the complexities faced the RM adaptation in the Egyptian airline industry. The research provides an original contribution to knowledge by creating a framework to overcome the complexities and challenges in adapting RM in the airline industry generally and the Egyptian airline industry particularly. The framework can be used as a RM tool to increase the effectiveness and efficiency of the Egyptian airline industry performance.

Keywords: revenue management, airline industry, revenue management complexity, Egyptian airline industry

Procedia PDF Downloads 388
1863 Built-Own-Lease-Transfer (BOLT): “An Alternative Model to Subsidy Schemes in Public Private Partnership Projects”

Authors: Nirali Shukla, Neel Shah

Abstract:

The World Bank Institute (WBI) is undertaking a review of government interventions aimed at facilitating sustainable investment in public private partnerships (PPPs) in various under developed countries. The study presents best practice for applying financial model to make PPPs financially viable. The lessons presented here, if properly implemented, can help countries use limited funds to attract more private investment, get more infrastructure built and, as a result, achieve greater economic growth. The four countries Brazil, Colombia, Mexico, and India in total develop an average of nearly US$50 billion in PPPs per year. There are a range of policies and institutional arrangements governments use to provide subsidies to PPPs. For example, some countries have created dedicated agencies, or ‘funds’, capitalized with money from the national budget to manage and allocate subsidies. Other countries have established well-defined policies for appropriating subsidies on an ad hoc basis through an annual budget process. In this context, subsidies are direct fiscal contributions or grants paid by the government to a project when revenues from user fees are insufficient to cover all capital and operating costs while still providing private investors with a reasonable rate of return. Without subsidies, some infrastructure projects that would provide economic or social gains, but are not financially viable, would go undeveloped. But the Financial model of BOLT (PPP) model described in this study suggests that it is most feasible option rather than going for subsidy schemes for making infrastructure projects financially viable. The major advantage for implementing this model is the government money is saved and can be used for other projects as well as the private investors are getting better rate of return than subsidized schemes.

Keywords: PPP, BOLT, subsidy schemes, financial model

Procedia PDF Downloads 745
1862 Charter versus District Schools and Student Achievement: Implications for School Leaders

Authors: Kara Rosenblatt, Kevin Badgett, James Eldridge

Abstract:

There is a preponderance of information regarding the overall effectiveness of charter schools and their ability to increase academic achievement compared to traditional district schools. Most research on the topic is focused on comparing long and short-term outcomes, academic achievement in mathematics and reading, and locale (i.e., urban, v. Rural). While the lingering unanswered questions regarding effectiveness continue to loom for school leaders, data on charter schools suggests that enrollment increases by 10% annually and that charter schools educate more than 2 million U.S. students across 40 states each year. Given the increasing share of U.S. students educated in charter schools, it is important to better understand possible differences in student achievement defined in multiple ways for students in charter schools and for those in Independent School District (ISD) settings in the state of Texas. Data were retrieved from the Texas Education Agency’s (TEA) repository that includes data organized annually and available on the TEA website. Specific data points and definitions of achievement were based on characterizations of achievement found in the relevant literature. Specific data points include but were not limited to graduation rate, student performance on standardized testing, and teacher-related factors such as experience and longevity in the district. Initial findings indicate some similarities with the current literature on long-term student achievement in English/Language Arts; however, the findings differ substantially from other recent research related to long-term student achievement in social studies. There are a number of interesting findings also related to differences between achievement for students in charters and ISDs and within different types of charter schools in Texas. In addition to findings, implications for leadership in different settings will be explored.

Keywords: charter schools, ISDs, student achievement, implications for PK-12 school leadership

Procedia PDF Downloads 123
1861 Determination of Temperature Dependent Characteristic Material Properties of Commercial Thermoelectric Modules

Authors: Ahmet Koyuncu, Abdullah Berkan Erdogmus, Orkun Dogu, Sinan Uygur

Abstract:

Thermoelectric modules are integrated to electronic components to keep their temperature in specific values in electronic cooling applications. They can be used in different ambient temperatures. The cold side temperatures of thermoelectric modules depend on their hot side temperatures, operation currents, and heat loads. Performance curves of thermoelectric modules are given at most two different hot surface temperatures in product catalogs. Characteristic properties are required to select appropriate thermoelectric modules in thermal design phase of projects. Generally, manufacturers do not provide characteristic material property values of thermoelectric modules to customers for confidentiality. Common commercial software applied like ANSYS ICEPAK, FloEFD, etc., include thermoelectric modules in their libraries. Therefore, they can be easily used to predict the effect of thermoelectric usage in thermal design. Some software requires only the performance values in different temperatures. However, others like ICEPAK require three temperature-dependent equations for material properties (Seebeck coefficient (α), electrical resistivity (β), and thermal conductivity (γ)). Since the number and the variety of thermoelectric modules are limited in this software, definitions of characteristic material properties of thermoelectric modules could be required. In this manuscript, the method of derivation of characteristic material properties from the datasheet of thermoelectric modules is presented. Material characteristics were estimated from two different performance curves by experimentally and numerically in this study. Numerical calculations are accomplished in ICEPAK by using a thermoelectric module exists in the ICEPAK library. A new experimental setup was established to perform experimental study. Because of similar results of numerical and experimental studies, it can be said that proposed equations are approved. This approximation can be suggested for the analysis includes different type or brand of TEC modules.

Keywords: electrical resistivity, material characteristics, thermal conductivity, thermoelectric coolers, seebeck coefficient

Procedia PDF Downloads 172
1860 Practical Modelling of RC Structural Walls under Monotonic and Cyclic Loading

Authors: Reza E. Sedgh, Rajesh P. Dhakal

Abstract:

Shear walls have been used extensively as the main lateral force resisting systems in multi-storey buildings. The recent development in performance based design urges practicing engineers to conduct nonlinear static or dynamic analysis to evaluate seismic performance of multi-storey shear wall buildings by employing distinct analytical models suggested in the literature. For practical purpose, application of macroscopic models to simulate the global and local nonlinear behavior of structural walls outweighs the microscopic models. The skill level, computational time and limited access to RC specialized finite element packages prevents the general application of this method in performance based design or assessment of multi-storey shear wall buildings in design offices. Hence, this paper organized to verify capability of nonlinear shell element in commercially available package (Sap2000) in simulating results of some specimens under monotonic and cyclic loads with very oversimplified available cyclic material laws in the analytical tool. The selection of constitutive models, the determination of related parameters of the constituent material and appropriate nonlinear shear model are presented in detail. Adoption of proposed simple model demonstrated that the predicted results follow the overall trend of experimental force-displacement curve. Although, prediction of ultimate strength and the overall shape of hysteresis model agreed to some extent with experiment, the ultimate displacement(significant strength degradation point) prediction remains challenging in some cases.

Keywords: analytical model, nonlinear shell element, structural wall, shear behavior

Procedia PDF Downloads 400
1859 Ability of Gastric Enzyme Extract of Adult Camel to Clot Bovine Milk

Authors: Boudjenah-Haroun Saliha, Isselnane Souad, Nouani Abdelwahab, Baaissa Babelhadj, Mati Abderrahmane

Abstract:

Algeria is experiencing significant development of the dairy sector, where consumption of milk and milk products increased by 2.7 million tons in 2008 to 4,400,000 tons in 2013, and cheese production has reached 1640 tons in the year 2014 with average consumption of 0.7 kg/person/year. Although rennet is still the most used coagulating enzyme in cheese, its production has been growing worldwide shortage. This shortage is primarily due to a growing increase in the production and consumption of cheese, and the inability to increase in parallel the production of rennet. This shortage has caused very large fluctuations in its price). To overcome these obstacles, much research has been undertaken to find effective and competitive substitutes used industrially. For this, the selection of a local production of rennet substitute is desirable. It would allow a permanent supply with limited dependence on imports and price fluctuations. Investigations conducted by our research team showed that extracts coagulants from the stomachs of older camels are characterized by a coagulating power than those from younger camels. The objective of this work is to study the possibility of substituting commercial rennet coagulant by gastric enzymes from adult camels for coagulation bovine milk. Excerpts from the raw camel coagulants obtained are characterized through their teneures proteins and clotting and proteolytic activities. Milk clotting conditions by the action of these extracts were optimized. Milk clotting time all treated with enzyme preparations and under different conditions was calculated. Bovine rennet has been used for comparison. The results show that crude extracts from gastric adult camel can be good substituting bovine rennet.

Keywords: Algeria, camel, cheese, coagulation, gastric extracts, milk

Procedia PDF Downloads 429
1858 Impact of Social Crisis on Property Market Performance and Evolving Strategy for Improved Property Transactions in Crisis Prone Environment: A Case Study of North Eastern Nigeria

Authors: A. Yakub AbdurRaheem

Abstract:

Urban violence in the form of ethnic and religious conflicts have been on the increase in many African cities in the recent years of which most of them are the result of intense and bitter competition for political power, the control of limited economic, social and environmental resources. In Nigeria, the emergence of the Boko Haram insurgency in most parts of the northeastern parts have ignited violence, bloodshed, refugee exodus and internal migration. Not only do the persistent attacks of the sect create widespread insecurity and fear, but it has also stifled normal processes of trade and investments most especially real property investment which is acclaimed to accelerate the economic cycle, thus the need to evolve strategies for an improved property market in such areas. This paper, therefore, examines the impact of this social crisis on effective and efficient utilization of real properties as a resource towards the development of the economy, using a descriptive analysis approach where particular emphasis was based on trends in residential housing values; volume of estimated property transactions and real estate investment decisions by affected individuals. Findings indicate that social crisis in the affected areas have been a clog on the wheels of property development and investment as properties worth hundreds of millions have been destroyed thereby having great impact on property values. Based on these findings, recommendations were made to include the need to strategically continue investing in property during such times, the need for Nigerian government to establish an active conflict monitoring and management unit for the prompt response, encourage community and neighborhood policing to ameliorate security challenges in Nigeria.

Keywords: social crisis, economy, resources, property market

Procedia PDF Downloads 230
1857 Infrared Photodetectors Based on Nanowire Arrays: Towards Far Infrared Region

Authors: Mohammad Karimi, Magnus Heurlin, Lars Samuelson, Magnus Borgstrom, Hakan Pettersson

Abstract:

Nanowire semiconductors are promising candidates for optoelectronic applications such as solar cells, photodetectors and lasers due to their quasi-1D geometry and large surface to volume ratio. The functional wavelength range of NW-based detectors is typically limited to the visible/near-infrared region. In this work, we present electrical and optical properties of IR photodetectors based on large square millimeter ensembles (>1million) of vertically processed semiconductor heterostructure nanowires (NWs) grown on InP substrates which operate in longer wavelengths. InP NWs comprising single or multiple (20) InAs/InAsP QDics axially embedded in an n-i-n geometry, have been grown on InP substrates using metal organic vapor phase epitaxy (MOVPE). The NWs are contacted in vertical direction by atomic layer deposition (ALD) deposition of 50 nm SiO2 as an insulating layer followed by sputtering of indium tin oxide (ITO) and evaporation of Ti and Au as top contact layer. In order to extend the sensitivity range to the mid-wavelength and long-wavelength regions, the intersubband transition within conduction band of InAsP QDisc is suggested. We present first experimental indications of intersubband photocurrent in NW geometry and discuss important design parameters for realization of intersubband detectors. Key advantages with the proposed design include large degree of freedom in choice of materials compositions, possible enhanced optical resonance effects due to periodically ordered NW arrays and the compatibility with silicon substrates. We believe that the proposed detector design offers the route towards monolithic integration of compact and sensitive III-V NW long wavelength detectors with Si technology.

Keywords: intersubband photodetector, infrared, nanowire, quantum disc

Procedia PDF Downloads 375