The Impact of Sea Level Rise on Roadway Design and Evacuation Routes in Delaware

As the global temperature continues to increase, the sea level continues to rise at a rapid rate that has never been seen before. This becomes an issue for many facets of life but one of the most impacted is the transportation infrastructure. Many people living in low elevation coastal areas can become trapped by flooding with no way in or out. With Delaware being a coastal state, this would affect a large portion of the population and will have detrimental effects over time if nothing is done to combat sea level rise. The issue with sea level rise in transportation is that once the roads become flooded, they become virtually unusable and detour routes would be needed. If all the roads in a coastal area were to be affected by sea level rise, the options for detours would become limited. This article looks at direct solutions to combat sea level rise and indirect solutions that would specifically help transportation infrastructure and evacuation routes in Delaware. There is not one solution that can fix every problem, so many solutions are laid out to see what is applicable to each affected area. Some solutions include defense structures that would be put close to the coast, raising the elevation of vulnerable roads throughout the state and including pumping stations to drain the water on the surface of the road. With an understanding of all these solutions around the world, the ultimate conclusion came in the form of a six-step plan that Delaware should take in order to best design against sea level rise in these coastal areas.

Evaluating the Feasibility of Road Diets for Advancing Urban Mobility in Newark, DE

Road Diets are far from a new technique for designers to apply to roadways. Yet after over 50 years of implementation and countless studies into their effectiveness, it is only relatively recently that the process is gaining widespread recognition and implementation. Each year, more states and countries are examining potential road diets and putting them into place. Still, there remains great skepticism and opposition in many corners. In addition, cities and states may be drawing from many of the same sources in how to go about the process of a road diet and evaluate them, yet their methodology, goals, and even terminology can vary from region to region. This study analyzes the implementation of a road diet along a one-way arterial road, in Newark, Delaware. The primary aim of this analysis is to evaluate the feasibility of introducing a dedicated bicycle infrastructure to enhance local accessibility and to quantify its potential impacts on traffic flow, parking availability, and loading logistics within the vicinity. While the reduction of one lane could be perceived as a constraint on traffic management, the investigation revealed that E Main Street, the roadway analyzed, for the most part, can adequately accommodate its traffic load with a single lane. Detailed findings underscore the notable enhancement in level of service and subsequent reduction in delay times across most surveyed approaches.

Targeted regeneration and upcycling of spent graphite by defect‐driven tin nucleation

The recycling of spent batteries has become increasingly important owing to their wide applications,abundant raw material supply,and sustainable development.Compared with the degraded cathode,spent anode graphite often has a relatively intact structure with few defects after long cycling.Yet,most spent graphite is simply burned or discarded due to its limited value and inferior performance on using conventional recycling methods that are complex,have low efficiency,and fail in performance restoration.Herein,we propose a fast,efficient,and“intelligent”strategy to regenerate and upcycle spent graphite based on defect‐driven targeted remediation.Using Sn as a nanoscale healant,we used rapid heating(~50 ms)to enable dynamic Sn droplets to automatically nucleate around the surface defects on the graphite upon cooling owing to strong binding to the defects(~5.84 eV/atom),thus simultaneously achieving Sn dispersion and graphite remediation.As a result,the regenerated graphite showed enhanced capacity and cycle stability(458.9 mAh g^(−1) at 0.2 A g^(−1) after 100 cycles),superior to those of commercial graphite.Benefiting from the self‐adaption of Sn dispersion,spent graphite with different degrees of defects can be regenerated to similar structures and performance.EverBatt analysis indicates that targeted regeneration and upcycling have significantly lower energy consumption(~99%reduction)and near‐zero CO2 emission,and yield much higher profit than hydrometallurgy,which opens a new avenue for direct upcycling of spend graphite in an efficient,green,and profitable manner for sustainable battery manufacture.

Geospatial Variability of Cholera Cases in Malawi Based on Climatic and Socioeconomic Influences

Cholera remains a public health threat in most developing countries in Asia and Africa including Malawi with seasonal recurrent outbreaks. Malawi’s recent Cholera outbreak in 2022 and 2023, exhibited higher morbidity and mortality rates than the past two decades. Lack of spatiotemporal-based technology and variability assessment tools in Malawi’s Cholera monitoring and management, limit our understanding of the disease’s epidemiology. The present work developed a spatiotemporal variability model for Cholera disease at district level and its relationship to socioeconomic and climatic factors based on cumulative confirmed Cholera cases in Malawi from March 2022 to July 2023 using Z-score statistic and multiscale geographically weighted regression (MGWR) in a Geographical Information System (GIS). We found out that socioeconomic factors such as access to safe drinking water, population density and poverty level, and climatic factors including temperature and rainfall strongly influenced Cholera prevalence in a complex and multifaceted manner. The model shows that Lilongwe, Mangochi, Blantyre and Balaka districts were highly vulnerable to Cholera disease followed by lakeshore districts of Salima, Nkhotakota, Nkhata-Bay and Karonga than other districts. We recommend strategic measures such as Water, Sanitation, and Hygiene (WASH) interventions, community awareness on proper water storage, Cholera case management, vaccination campaigns and spatial-based surveillance systems in the most affected districts. This research has shown that MGWR, as a surveillance system, has the potential of providing insights on the disease’s spatial patterns for public health authorities to identify high-risk districts and implement early response interventions to reduce the spread of the disease.

Optimization of the Physical Aperture of the Parabolic Reflector Antenna

In fields like astronomy and radar technology, high-gain antennas are required for long-distance communication. Due to its relatively large gain, the use of parabolic antennas has become very popular over time, because they can easily achieve gains of above 30 dB at microwave and higher frequencies. Today, most systems’ success depends on how well the antennas perform. These antennas are available in different types and sizes. Each antenna’s effective area usually has less than the actual physical area of the antenna surface. This means that the unused area of the antenna is massive, and a waste. The aim of the research is to show that the actual physical aperture of a parabolic antenna can be reduced as much as possible to equal the effective area, as given by the antenna formula, thereby saving manufacturing costs, improve the aesthetics. In other words, the focus of this work is to experimentally show that reflector antenna can be made of smaller sizes but better performance. Measurements were taken from different positions from a parabolic antenna, the signal level measured and compared with signal levels for optimal performance.

Utilization and Usability of Delaware Traffic Management Products: A Survey and Challenges

To address the growing problem of congestion, delays, and overall traffic issues, DelDOT (Delaware Department of Transportation) established the Transportation Management Center (TMC) in 1997. DelDOT-TMC also coordinates and manages DelDOT’s response to any incident that impacts the multimodal transportation system within the state of Delaware. Among other things, DelDOT-TMC collects traffic, roadway weather, and hydrological data using over a thousand monitoring devices installed throughout the state of Delaware. After data has been obtained, DelDOT-TMC analyzes and disseminates real-time travel information to the public through DelDOT’s website (online interactive maps), smartphone application, traffic advisory radio, and social media sites such as Twitter, Facebook, YouTube, Blog, and Flickr;however, the utilization and usability of this information by the public are, for the most part, unknown. The purpose of this study is to evaluate the global responsibilities of DelDOT-TMC and assess the process that DelDOT-TMC uses to gather, process, analyze, and distribute traffic and roadway weather data to the public. The study employs a survey to assess the utilization of DelDOT-TMC’s products, i.e., DelDOT Mobile App, WTMC 1380 AM travel advisory radio, DelDOT’s public website, DelDOT’s social media, as well as the usability of the DelDOT mobile app to check DART (Delaware Authority for Regional Transportation) First State transit service schedules.

Effects of contact/collision sport history on gait in early-to mid-adulthood

Background:To determine the effect of contact/collision sport participation on measures of single-task(ST)and dual-task(DT)gait among early-to middle-aged adults.Methods:The study recruited 113 adults(34.88±11.80 years,(mean±SD);53.0%female)representing 4 groups.Groups included(a)former non-contact/collision athletes and non-athletes who are not physically active(n=28);(b)former non-contact/collision athletes who are physically active(n=29);(c)former contact/collision sport athletes who participated in high-risk sports and are physically active(n=29);and(d)former rugby players with prolonged repetitive head impact exposure history who are physically active(n=27).Gait parameters were collected using inertial measurement units during ST and DT gait.DT cost was calculated for all gait parameters(double support,gait speed,and stride length).Groups were compared first using one-way analysis of covariance.Then a multiple regression was performed for participants in the highrisk sport athletes and repetitive head impact exposure athletes groups only to predict gait outcomes from contact/collision sport career duration.Results:There were no significant differences between groups on any ST,DT,or DT cost outcomes(p>0.05).Contact/collision sport duration did not predict any ST,DT,or DT cost gait outcomes.Conclusion:Years and history of contact/collision sport participation does not appear to negatively affect or predict neurobehavioral function in early-to mid-adulthood among physically active individuals.

Incorporation of the 8th Edition AJCC/TNM Staging of Carcinoma of the Appendix into the Esquivel Peritoneal Surface Disease Severity Score (E-PSDSS) in 229 Patients with Mucinous Appendiceal Neoplasms

Introduction: A practical staging classification that has prognostic significance in mucinous appendiceal neoplasms represents an unmet need in oncology. The purpose of this study is to present a second edition of the PSDSS in mucinous appendiceal neoplasms with or without peritoneal dissemination based on the AJCC/TNM 8th edition. Materials and Methods: We analyzed 229 patients based on the AJCC/TNM 8th edition incorporating G (grade) and E (extent of disease). The impact of these 5 clinicopathological variables (T, N, M, G, E) is scored as stages 0 to IV and is reported as the Esquivel Peritoneal Surface Disease Severity Score (E-PSDSS). Results: One hundred and seventy-three patients underwent cytoreductive surgery (CRS) and HIPEC. There were 30 (13.1%), 56 (24.4%), 48 (20.9%), 20 (8.7%) and 75 (32.7%) patients with E-PSDSS 0, I, II, III, and IV, respectively. Five-year overall survival was 100%, 100%, 84.46%, 52.29% and 12.92% for E-PSDSS 0, I, II, III and IV, respectively (p Conclusion: The E-PSDSS combines specimen examination and reporting according to the College of American Pathologists with the pTNM requirements from the AJCC staging manual. It represents an important prognostic indicator in patients with mucinous appendiceal neoplasms.

Challenges in the Detection and Attribution of Northern Hemisphere Surface Temperature Trends Since 1850

Since 2007,the Intergovernmental Panel on Climate Change(IPCC)has heavily relied on the comparison between global climate model hindcasts and global surface temperature(ST)estimates for concluding that post-1950s global warming is mostly human-caused.In Connolly et al.,we cautioned that this approach to the detection and attribution of climate change was highly dependent on the choice of Total Solar Irradiance(TSI)and ST data sets.We compiled 16 TSI and five ST data sets and found by altering the choice of TSI or ST,one could(prematurely)conclude anything from the warming being“mostly human-caused”to“mostly natural.”Richardson and Benestad suggested our analysis was“erroneous”and“flawed”because we did not use a multilinear regression.They argued that applying a multilinear regression to one of the five ST series re-affirmed the IPCC's attribution statement.They also objected that many of the published TSI data sets were out-of-date.However,here we show that when applying multilinear regression analysis to an expanded and updated data set of 27 TSI series,the original conclusions of Connolly et al.are confirmed for all five ST data sets.Therefore,it is still unclear whether the observed warming is mostly human-caused,mostly natural or some combination of both.

The Impact of Satellite Communications on Environmental Hazard Control: Tool for the Realization of African Union Agenda 2063 Aspirations

Africa is a developing economy and as such, emphasis has been placed on the achievement of revolutionary goals that will place her on a similar rank as the developed economies. Pertaining to this objective, Heads of States and government all over Africa instigated the African Union (AU) Agenda 2063, which is a framework put in place to achieve a continental transformation over the next 40 years. The use of satellites has been proven to be a major influence on economic growth since it facilitates the exchange of information. Environmental hazards such as climate changes, pollution, and inefficient waste management can be classified as one of the drawbacks to achieving this economic growth we hope to accomplish. The purpose of this paper is to analyze and examine satellite communication as a tool for the attainment of an integrated, prosperous and peaceful Africa by means of combatting environmental hazards in the continent.

International study of the Complex Stress Reaction Syndrome:Implications for transdiagnostic clinical practice

BACKGROUND The debate regarding diagnostic classification systems in psychiatry(categorial vs dimensional systems)has essential implications for the diagnosis,prevention and treatment of stress reactions.We previously found a unique pattern of stress reaction in a study executed during the coronavirus disease 2019 pandemic using large representative samples in two countries,and termed it the Complex Stress Reaction Syndrome(CSRS).AIM To investigate CSRS,Type A(psychiatric symptoms,spanning anxiety,depression,stress symptoms,and posttraumatic stress disorder(PTSD)),with or without long-coronavirus disease(COVID)residuals(CSRS,Type B,neuropsychiatric symptoms spanning cognitive deficits and fatigue,excluding systemic symptoms).Our two-tailed hypothesis was that CSRS is a condition related to an unrecognized type of stress reaction in daily life in the general population(Type A)or that it is related to the severe acute respiratory syndrome coronavirus 2 infection and its long-COVID residuals(Type B).METHODS 977 individuals in four continents(North America,Europe,Australia and the Middle East)completed the online study questionnaire in six languages using the Qualtrics platform.The study was managed by six teams in six countries that promoted the study on social media.The questionnaire assessed anxiety,depression,stress symptoms and PTSD(CSRS,Type A),cognitive deficits and fatigue(CSRS,Type B).The data were analyzed using Proportion Analyses,Multivariate Analysis of Co-Variance(MANCOVA),linear regression analyses and validated clinical cutoff points.RESULTS The results of the Proportion Analyses showed that the prevalence of 4 symptoms spanning anxiety,depression,stress symptoms,and PTSD was significantly higher than the most prevalent combinations of fewer symptoms across 4 continents,age groups,and gender.This supports the transdiagnostic argument embedded in the CSRS(Type A).The same pattern of results was found in infected/recovered individuals.The prevalence of the 4 psychiatric symptoms combination was significantly greater than that of 5 and 6 symptoms,when adding cognitive deficits and fatigue,respectively.MANCOVA showed a significant three-way interaction(age×gender×continent).Further analyses showed that the sources of this three-way interaction were threefold relating to two sub-populations at-risk:(1)Individuals that self-identified as non-binary gender scored significantly higher on all 4 psychiatric symptoms of the CSRS,Type A at young age groups(<50 years old)in North America compared to(self-identified)women and men located in the 4 continents studied,and to other ages across the adult life span;and(2)This pattern of results(CSRS,Type A)was found also in women at young ages(<40 years old)in North America who scored higher compared to men and women in other continents and other ages.Linear regression analyses confirmed the MANCOVA results.CONCLUSION These results show a combined mental health risk factor related to stress reactivity,suggesting that the CSRS is sensitive to populations at risk and may be applied to future identification of other vulnerable sub-populations.It also supports the transdiagnostic approach for more accurate prevention and treatment.Time will tell if such transdiagnostic syndromes will be part of the discussions on the next revisions of the traditional classification systems or whether the crisis in psychiatry further evolves.

A Local Macroscopic Conservative(LoMaC)Low Rank Tensor Method with the Discontinuous Galerkin Method for the Vlasov Dynamics

In this paper,we propose a novel Local Macroscopic Conservative(LoMaC)low rank tensor method with discontinuous Galerkin(DG)discretization for the physical and phase spaces for simulating the Vlasov-Poisson(VP)system.The LoMaC property refers to the exact local conservation of macroscopic mass,momentum,and energy at the discrete level.The recently developed LoMaC low rank tensor algorithm(arXiv:2207.00518)simultaneously evolves the macroscopic conservation laws of mass,momentum,and energy using the kinetic flux vector splitting;then the LoMaC property is realized by projecting the low rank kinetic solution onto a subspace that shares the same macroscopic observables.This paper is a generalization of our previous work,but with DG discretization to take advantage of its compactness and flexibility in handling boundary conditions and its superior accuracy in the long term.The algorithm is developed in a similar fashion as that for a finite difference scheme,by observing that the DG method can be viewed equivalently in a nodal fashion.With the nodal DG method,assuming a tensorized computational grid,one will be able to(i)derive differentiation matrices for different nodal points based on a DG upwind discretization of transport terms,and(ii)define a weighted inner product space based on the nodal DG grid points.The algorithm can be extended to the high dimensional problems by hierarchical Tucker(HT)decomposition of solution tensors and a corresponding conservative projection algorithm.In a similar spirit,the algorithm can be extended to DG methods on nodal points of an unstructured mesh,or to other types of discretization,e.g.,the spectral method in velocity direction.Extensive numerical results are performed to showcase the efficacy of the method.

Space/Air Covert Communications:Potentials,Scenarios,and Key Technologies

Space/air communications have been envisioned as an essential part of the next-generation mobile communication networks for providing highquality global connectivity. However, the inherent broadcasting nature of wireless propagation environment and the broad coverage pose severe threats to the protection of private data. Emerging covert communications provides a promising solution to achieve robust communication security. Aiming at facilitating the practical implementation of covert communications in space/air networks, we present a tutorial overview of its potentials, scenarios, and key technologies. Specifically, first, the commonly used covertness constraint model, covert performance metrics, and potential application scenarios are briefly introduced. Then, several efficient methods that introduce uncertainty into the covert system are thoroughly summarized, followed by several critical enabling technologies, including joint resource allocation and deployment/trajectory design, multi-antenna and beamforming techniques, reconfigurable intelligent surface(RIS), and artificial intelligence algorithms. Finally, we highlight some open issues for future investigation.

Oxidation of As(Ⅲ) by potassium permanganate

The oxidation of As（Ⅲ） with potassium permanganate was studied under conditions including pH, initial As（Ⅲ） concentration and dosage of Mn（Ⅶ）. The results have shown that potassium permanganate was an effective agent for oxidation of As（Ⅲ） in a wide pH range. The pH value of tested water was not a significant factor affecting the oxidation of As（Ⅲ） by Mn（Ⅲ）. Although theoretical redox analyses suggest that Mn（Ⅶ） should have better performance in oxidization of As（Ⅲ） within lower pH ranges, the experimental results show that the oxidation efficiencies of As（Ⅲ） under basic and acidic conditions were similar, which may be due to the adsorption of As（Ⅲ） on the Mn（OH）2 and MnO2 resulting from the oxidation of As（Ⅲ）.

The influence of moisture on the permeability of crushed shale samples

Shale cuttings and cores recovered from the subsurface and stored for hours to decades tend to dry out and lose moisture and hydrocarbons,leading to an increase in the effective matrix permeability.Moisture loss in shale samples is a fundamental sample preservation problem which can be solved by applying a standard moisture equilibration procedure to restore lost moisture.Our aim was to investigate the relationship between permeability and variable moisture as-received,as-received moisture-equilibrated and saturated moisture-equilibrated samples.Samples were crushed to a series of particle sizes(0.6-2.0)mm and moisture equilibrated at 97% relative humidity.Results show that moisture equilibration in the samples was achieved after 72 h.The permeability of the saturated moisture-equilibrated and as-received moisture-equilibrated samples decreased exponentially with increase in moisture content.The high correlation coefficient between permeability and particle size(r = 0.96 and 0.97)for moisture-equilibrated samples compared to 0.76 for as-received samples indicates that moisture equilibration improves permeability measurements in crushed shale samples.Furthermore,permeability measurements are repeatable for moisture-equilibrated samples compared to samples that were not equilibrated(as-received).We conclude that moisture content affects permeability and moisture equilibration normalizes and improves the repeatability of permeability measurements in crushed shale.

Review of Maritime Transportation Air Emission Pollution and Policy Analysis

The study of air emission in maritime transportation is new, and the recognition of its importance has been rising in the recent decade. The emissions of CO2, SO2, NO2 and particulate matters from maritime transportation have contributed to climate change and environmental degradation. Scientifically, analysts still have controversies regarding how to calculate the emissions and how to choose the baseline and methodologies. Three methods are generally used, namely the 'bottom up' approach, the 'top down' approach and the STEEM, which produce very different results, leading to various papers with great uncertainties. This, in turn, results in great difficulties to policy makers who attempt to regulate the emissions. A recent technique, the STEEM, is intended to combine the former two methods to reduce their drawbacks. However, the regulations based on its results may increase the costs of shipping companies and cause the competitiveness of the port states and coastal states. Quite a few papers have focused on this area and provided another fresh perspective for the air emission to be incorporated in maritime transportation regulations; these facts deserve more attention. This paper is to review the literature on the debates over air emission calculation, with particular attention given to the STEEM and the refined estimation methods. It also reviews related literature on the economic analysis of maritime transportation emission regulations, and provides an insight into such analysis. At the end of this paper, based on a review and analysis of previous literature, we conclude with the policy indications in the future and work that should be done. As the related regulations in maritime transportation emissions are still at their beginning stage in China, this paper provides specific suggestions on how China should regulate emissions in the maritime transportation sector.

Pedestrian Facilities Capacity and Level of Service at Intersections in a Connected and Autonomous Vehicle Environment

It is inevitable that Connected and Autonomous Vehicles (CAVs) will be a major focus of transportation and the automotive industry with increased use in future traffic system analysis. Numerous studies have focused on the evaluation and potential development of CAVs technology;however, pedestrians and bicyclists, as two essential and important modes of the road users have seen little to no coverage. In response to the need for analyzing the impact of CAVs on non-motorized transportation, this paper develops a new model for the evaluation of the Level of Service (LOS) for pedestrians in a CAVs environment based on the Highway Capacity Manual (HCM). The HCM provides a methodology to assess the level of service for pedestrians and bicyclists on various types of intersections in urban areas. Five scenarios were created for simulation via VISSIM (a software) that corresponds to the different proportions of the CAVs and different signal systems in a typical traffic environment. Alternatively, the Surrogate Safety Assessment Model (SSAM) was selected for analyzing the safety performance of the five scenarios. Through computing and analyzing the results of simulation and SSAM, the latter portion of this paper focuses on the development of a new model for evaluating pedestrian LOS in urban areas which are based upon HCM standards which are suitable for CAVs environments. The results of this study are intended to inform the future efforts of engineers and/or policymakers and to provide them with a tool to conduct a comparison of capacity and LOS related to the impact of CAVs on pedestrians during the process of a transportation system transition to CAVs.

An Interactive Expert System Based Decision Making Model for the Management of Transit System Alternate Fuel Vehicle Assets

Traditionally, the process used by public transportation entities to determine the acquisition strategy for new vehicle asset is based upon a broad range of criteria. Vehicle cost has been cited as one of the more critical factors which decision makers consider. It is currently a common practice to consider other factors (life-cycle cost, fuel efficiency, vehicle reliability, environmental effects, etc.) that contribute to a more comprehensive approach. This study investigates the next generation of advancements in decision making tools in the area of the application of methods to quantify and manage uncertainty. In particular, the uncertainty comes from the public policy arena where future policy and regulations are not always based upon logical and predictable processes. The fleet decision making process in most governmental agencies is a very complex and interdependent activity. There are always competing forces and agendas within the view of the decision maker. Rarely is the decision maker a single person although, within the transit environment, there is often one person charged with the responsibility of fleet management. The focus of this research examines the decision making of the general transit agency community via the development of an expert systems prototype tool. A computer-based prototype system is developed which provide an expert knowledge-based recommendation, based upon variable user inputs. The results shown in this study show that a decision making tool for the management of transit system alternate fuel vehicle assets can be modeled and tested. The direct users of this research are the transit agency administrations. The results can be used by the management teams as a reliable input to inform their urban transit buses expansion decision making process.

Origin of Room-Temperature Ferromagnetism for Cobalt-Doped ZnO Diluted Magnetic Semiconductor

The pure single phase of Zn0.95 Co0.05 O bulks is successfully prepared by solid-state reaction method. The effects of annealing atmosphere on room-temperature ferromagnetic behaviour for the Zn0.95 Co0.05 O bulks are investigated. The results show that the air-annealed samples has similar weak ferromagnetic behaviour with the as-sintered samples, but the obvious ferromagnetic behaviour is observed for the samples annealed in vacuum or Ar/H2 gas, indicating that the strong ferromagnetism is associated with high oxygen vacancies density. High saturation magnetization Ms = 0.73μg/Co and coercivity Hc = 233.8 Oe are obtained for the Ar/H2 annealed samples with pure single phase structure. The enhanced room-temperature ferromagnetic behaviour is also found in the samples with high carrier concentration controlled by doping interstitials Zn （Zni）.

Assembly and Applications of Carbon Nanotube Thin Films

The ultimate goal of current research on carbon nanotubes （CNTs） is to make breakthroughs that advance nanotechnological applications of bulk CNT materials. Especially, there has been growing interest in CNT thin films because of their unique and usually enhanced properties and tremendous potential as components for use in nano-electronic and nano-mechanical device applications or as structural elements in various devices. If a synthetic or a post processing method can produce high yield of nanotube thin films, these structures will provide tremendous potential for fundamental research on these devices. This review will address the synthesis, the post processing and the device applications of self-assembled nanotube thin films.