Drop In Intensity Research Articles

Experimental investigation of flame fluctuation reduction in distributed combustion

Analysis of dynamic combustor stability is essential for the development of practical devices that employ distributed reaction zones. The fluctuation of reaction zone (RZ) was studied to compare normal air combustion and distributed combustion at an equivalence ratio of 0.9 in a swirl-stabilized burner using methane fuel. Distributed combustion was fostered by diluting the inlet air stream with carbon dioxide that resulted in a gradual drop in the adiabatic flame temperature (Tad). High-speed broadband chemiluminescence at 3 kHz was used to study the global combustion dynamics. Vortex shedding observed along the shear layers influenced the oscillation of flame base in normal air combustion. However, relatively stable bases were observed in distributed combustion. Fast Fourier Transformation performed on RZ base fluctuation data supported the observations from chemiluminescence signatures. Proper orthogonal decomposition (POD) analysis indicated various vortex-shedding patterns as the dominant structures in conventional swirl flames. The power spectral density (PSD) of POD modes showed the rotational effect of RZ and weak von Karman vortex shedding to influence fluctuation in distributed combustion. The self-sustained flame oscillations in normal swirl flames were investigated from the acoustic and heat release fluctuation signals. Both acoustic and heat release fluctuations gradually reduced when approaching the distributed combustion. The PSD of these signals demonstrated a common peak at ~ 174 Hz (in normal swirl flames) with possible thermo-acoustic coupling. This peak was consistent with the peaks obtained from the base fluctuation and POD spectra. The peak gradually diminished when approaching the state of distributed combustion. A similar observation of gradually decreasing acoustic and heat release fluctuation was made with a constant Tad. However, the drop in chemiluminescence signal intensity with CO2 dilution was relatively low in case of constant Tad compared to the variable Tad case. The local and global Rayleigh index obtained for the variable Tad cases at different dilution levels showed positive values at O2 = 21 and 20%, which signified self-sustained instability. However, the distributed combustion possessed a negative Rayleigh index indicating dampening of instability. These results support the gradual decline of thermo-acoustic instability when approaching the distributed combustion condition.

Justifcation for the usage of mineral water of Teberda deposit in the treatment of patients with focal pulmonary tuberculosis

The purpose of the research is scientifically substantiate the use of drinking mineral waters (MW) of Teberdinskiy deposit in sanatorium and spa treatment of patients suffering from focal pulmonary tuberculosis (FPT).
 Material and methods. The study included 80 patients with FPT in the resorption and carnification phase. By random sampling, we formed 2 groups: the control group (CG; 40 people) that received inhalations with 1% dioxidin solution and a standard drug anti-tuberculosis chemotherapy; the patients of the group of comparison (GC; 40 people) additionally received drinking MW "Teberda."
 Results. The analysis of clinical symptom dynamics did not show any significant differences between the groups: by the end of sanatorium-and-spa treatment the leveling of clinical symptoms in the MG was with 98.3% of the cases, in the CG with 88.8%. The patients of the MG had a normalization of related T-lymphocyte subpopulations, immunoregulatory index decreased by 39.2% (p 0.01), there was a drop in intensity of free radical oxidation by 30.2% (p 0.01), an increase in activity of antioxidant protection system by 17.2% (p 0.05). The CG had only a tendency to improvement of laboratory indicators.
 Conclusion. In order to achieve a higher therapeutic effect having FPT in the resorption and carnification phase, it is advisable to include drinking MW in the treatment program, which expands and complements the possibilities of rehabilitation and rehabilitation assistance to the given group of patients.

Post dry etching treatment of nanopillar GaN/InGaN multi-quantum-wells

Time-resolved photoluminescence (PL), current-voltage characteristics and deep trap spectra of nanopillar GaN/InGaN multi-quantum-well (MQW) light emitting diodes (LEDs) prepared by reactive ion etching (RIE) from planar samples were studied as a function of post-RIE surface treatment. Immediately after RIE, we observe a sharp drop of intensity of the 460 nm MQW PL band and a strong increase of intensity of the defect-related 600 nm MQW band similar to the yellow band in n-GaN. KOH etching and (NH4)2S sulfur passivation treatments increased the MQW PL band intensity above the level of the planar structure and decreased the intensity of the defect 600 nm PL band, but was not effective in decreasing the RIE-induced excessive leakage current of the LEDs. Only annealing at ≥ 700 °C following RIE was able to strongly suppress the excessive leakage. Deep trap spectra suggest that the RIE-induced drop of the 460 nm PL intensity and increase of the 600 nm PL intensity are accompanied by the increase of the Ec-0.7 eV electron trap density and of Ev+0.8 eV hole trap density in the quantum wells. The first of these defects is attributed to nitrogen interstitial acceptors believed to be effective nonradiative recombination centers, while the hole traps are attributed to gallium vacancy acceptor complexes with shallow donors. Both types of defects are produced on the sidewalls of nanopillars by RIE and can be largely annealed at 700 °C, although higher annealing temperatures are needed to fully suppress their negative impact. These results are also relevant to curing the effects of dry-etch damage for micro-LEDs with small chip dimensions, a serious problem in the micro-LED field.

Mechanism and detection of oscillatory flow in a supersonic cascade

The throttling process in a supersonic cascade is investigated in a free-jet wind tunnel at Mach 2.4. High-speed schlieren imaging and high-resonance frequency pressure measurements are used to capture the flow features. A flap is placed at the channel exit to choke the flow linearly. In the throttling process before the onset of oscillatory flow, the shock train leading shock leads to large area of flow separation near the suction surface and high total pressure loss. The oscillatory flow is triggered by the expansion of the flow separation induced by the impingement of the shock train leading shock onto the suction surface, which belongs to the Dailey criterion. The alarm is triggered during oscillatory flow detection, based on the pressure data at the optimal S5 transducer, either before the large-amplitude pressure fluctuation begins or after it ends. Comparing with other algorithms, the derivative-based algorithm has no data to be stored and no expensive calculation is the best technique for detection. To adjust the alarm margin, three detection points are set upstream of the S5 transducer and detection is performed based on the schlieren images. All algorithms detect the sudden drop in light intensity caused by the arrival of the shock train leading shock at the detection location. The alarm margin is the largest at point C, which is farthest from the suction surface tip, and smallest at point A, which is closest to the suction surface tip.

Di-carbonyl-o-semiquinonato rhodium complexes

Two novel dicarbonyl-semiquinonato rhodium complexes were synthesized and studied. Complexes are analogues of (CO)2Rh(3,6-DBSQ) (3,6-DBSQ-3,6-di-tert-butyl-o-benzosemiquinone) which thread-like crystals can bend reversibly under light or heat activation (G.A. Abakumov, V.I. Nevodchikov, Dokl. Acad. Nauk SSSR 1982, 266, 1407–1410). Complexes differ from (CO)2Rh(3,6-DBSQ) by substituents in 3,6-positions of quinonato ring (cyclohexyl (1) and isopropyl (2) instead of tert-butyl). Single crystal structural study indicates that both complexes are the derivatives of Rh(I) with o-semiquinonato anion-radical. Molecules form pairs due the short contacts in contrast to (CO)2Rh(3,6-DBSQ) and other similar compounds which form the endless alternated chains with direct Rh-Rh bond. At that, complex 1 molecules form isolated pairs, whereas molecules of 2 can be united in the chain. Both compounds 1 and 2 have the array of intensive bands in IR spectrum in the region 1350 cm−1 which is closer to bond stretch vibrations of C–O ordinary bond but not sesquilateral. EPR of solutions of complexes indicates presence of monomeric complex molecules where the single unpaired electron is localized in o-semiquinonato ligand. The drop of EPR signal intensity with cooling of solutions of 1 and 2 evidence that the association process takes place.

Health systems effects of successive emergency health and nutrition projects: an embedded retrospective case study analysis in Sudan and Pakistan.

Despite increasing attention to the concept of a humanitarian-development nexus in recent years, limited research is available to improve health systems strengthening practice within humanitarian programmes. We used an exploratory, systematic, embedded, multiple case study design to discern systems effects of successive Save the Children chronic emergency health and nutrition projects implemented in Sudan and Pakistan between 2011 and 2018. We used textual analysis to code 63 documents focused on eight themes using NVivo 11.0. This was supplemented by six key informant interviews. Findings offer a complex and mixed picture, with contributions to systems strengthening in community systems, their linkages to health management structures, and human resources for health. Projects with primary mandates for urgent service delivery progressively found systems strengthening opportunities, through a combination of tacit choices and explicit objectives. In both countries, some 'parallel systems' were set in place initially, with immediate gains (e.g. quality of services) only occasionally accompanied by enhanced systems capacity to sustain them. Cycles of implementation, however, achieved financial transition of 'macro-costs' to the government (e.g. facilities in Sudan, staff in Pakistan) through indirect pathways and the influence of pluralistic governmental structures themselves. Opportunities were taken, or missed, based on dynamic relationships within the government-development partners eco-system. Transition steps also came with unintended effects and drops in intensity. Both project contributions to systems strengthening and our own study were limited by substantial gaps in evaluation and documentation processes. We provide cautious recommendations based on the literature and our two case studies. Even mid-size chronic emergency projects can and should make meaningful and explicit contributions to systems strengthening. This contribution will, however, depend on the development eco-system context, and development of better collective intelligence (coordination, evaluation and learning, benchmarking, accountability) to improve individual projects' adaptive management efforts to improve fit with evolving national systems.

Tracking economic activity in response to the COVID-19 crisis using nighttime lights – The case of Morocco

Over the past decade, nighttime lights have become a widely used proxy for measuring economic activity. This paper examines the potential for high frequency nighttime lights data to provide “near real-time” tracking of the economic impacts of the COVID-19 crisis in Morocco. At the national level, there exists a statistically significant correlation between quarterly movements in Morocco's overall nighttime light intensity and movements in its real GDP. This finding supports the cautious use of lights data to track the economic impacts of the COVID-19 crisis at higher temporal frequencies and at the subnational and city levels, for which GDP data are unavailable. Relative to its pre-COVID-19 trend growth path of lights, Morocco experienced a large drop in the overall intensity of its lights in March 2020 following the country's first COVID-19 case and the introduction of strict lockdown measures, from which it has subsequently struggled to recover. At the subnational and city levels, while all regions and cities examined shared in March's national decline in nighttime light intensity, some suffered much larger declines than others. Since then, the relative effects of the COVID-19 shock across regions and cities appear to have largely persisted. Notwithstanding these findings, however, further research is required to ascertain the exact causes of the observed changes in light intensity and to fully verify that the results are driven by anthropogenic causes.

Ligand-controlled and nanoconfinement-boosted luminescence employing Pt(ii) and Pd(ii) complexes: from color-tunable aggregation-enhanced dual emitters towards self-referenced oxygen reporters.

In this work, we describe the synthesis, structural and photophysical characterization of four novel Pd(ii) and Pt(ii) complexes bearing tetradentate luminophoric ligands with high photoluminescence quantum yields (ΦL) and long excited state lifetimes (τ) at room temperature, where the results were interpreted by means of DFT calculations. Incorporation of fluorine atoms into the tetradentate ligand favors aggregation and thereby, a shortened average distance between the metal centers, which provides accessibility to metal–metal-to-ligand charge-transfer (3MMLCT) excimers acting as red-shifted energy traps if compared with the monomeric entities. This supramolecular approach provides an elegant way to enable room-temperature phosphorescence from Pd(ii) complexes, which are otherwise quenched by a thermal population of dissociative states due to a lower ligand field splitting. Encapsulation of these complexes in 100 nm-sized aminated polystyrene nanoparticles enables concentration-controlled aggregation-enhanced dual emission. This phenomenon facilitates the tunability of the absorption and emission colors while providing a rigidified environment supporting an enhanced ΦL up to about 80% and extended τ exceeding 100 μs. Additionally, these nanoarrays constitute rare examples for self-referenced oxygen reporters, since the phosphorescence of the aggregates is insensitive to external influences, whereas the monomeric species drop in luminescence lifetime and intensity with increasing triplet molecular dioxygen concentrations (diffusion-controlled quenching).

Blame the Foreigners? Exports and Sulfur Dioxide Emissions in China

This paper provides an overhaul of the contribution of exports to industrial sulfur dioxide (SO2) emissions in Chinese cities. My estimation strategy exploits the import demand shocks of export destination markets (net of their demand for Chinese products) as a plausibly exogenous source of variation in the cities' exports. The baseline results show that a 10 percentage-point increase in export shock (weighted by the exporting industry's relative emission intensity) leads to a 1.6 percentage-point rise in SO2 emissions, equivalent to a 635-ton increase per year for an average Chinese city. This estimate remains qualitatively stable to an array of robustness checks by accounting for: alternative controls for production for domestic sales shocks, the city market share in global trade, and the influence of a lagged impact of foreign demand shocks. Tentative evidence also suggests that production for exports does not contribute to nationwide emission intensity drop. A further anatomy shows with weak evidence that foreign-owned firms and deeper contractual links with the global production network could play a positive role in reducing the environmental footprint of industrial activities.

Models for Predicting the Jet Trajectory and Intensity Drop Point of Fire Monitors

Two models are defined for predicting the trajectory of a foam jet originating from a fire monitor (hydrant) and the related intensity drop point. An experimental framework is also defined and used accordingly to compare real-time data with the predictions of such models. This mixed theoretical-experimental approach is proven to be effective for the determination of otherwise unknown coefficients which take into account several important factors such as the operation pressure, the elevation angle and the nozzle diameter. It is shown that the mean absolute error is smaller than 20%.

Rio de Janeiro noise mapping during the COVID-19 pandemic period

Abstract This paper presents a comparison between the acoustic scenario at the Rio de Janeiro city center, before and during the COVID-19 pandemic. Undergoing one of the most important pandemics of the recent history, the social isolation led to a new acoustic scenario for Rio de Janeiro. The study was realized at the city center, an area of historical, economic and cultural relevance. The comparison consisted of analyzing measured data and noise maps produced for the city center area. The maps were created according to measured and collected data of the respective time periods. The acoustic scenario prior to the pandemic time was reconstructed based on previous measurements and data collection, while the pandemic one was built with data survey during the highest social isolation index on July 2020. The comparative analysis showed a considerable noise reduction, between 10 and 15 dB, for areas where the traffic noise was not intense and where the human activities were predominant on the streets. However, there was no substantial noise decrease for the areas around the major avenues. This occurred due to the traffic intensity drop to 50% during the pandemic, which meant a noise reduction between 3 and 5 dB.

Padrão de inserção da mulher negra no mercado de trabalho nordestino: notas para o período 2005-2014

Este ensaio se propõe ao entendimento de como tem sido processada a inserção da mulher negra no mercado de trabalho do Nordeste. Utiliza-se de metodologia descritiva, com base em revisão de literatura e na análise de dados secundários, que ocorre sob a perspectiva de raça e gênero, através da definição de quatro categorias: mulher negra (preta e parda), mulher não negra, homem negro (preto e pardo) e homem não negro. Os dados são provenientes dos microdados da Pesquisa Nacional por Amostra de Domicílios (PNAD), do Instituto Brasileiro de Geografia e Estatística (IBGE), para os anos de 2005 e 2014. Os resultados mostram que melhoria das condições econômicas e do mercado de trabalho experimentada pelo Brasil, especialmente nos anos 2000, ampliam as oportunidades reservadas às mulheres e se estendem, embora de forma diferenciada, condicionando um novo padrão de inserção das mulheres negras no mercado de trabalho. Todavia, apesar da melhoria inconteste de um conjunto de indicadores relativos à mulher negra, como o meselhor ritmo de crescimento da população ocupada, queda mais intensa do desemprego, maior variação da média de anos de estudo, além de ganhos significativos de participação em melhores faixas de escolaridade, a face do desemprego e da informalidade ainda é negra e feminina, o que demonstra o longo caminho a ser percorrido em busca de políticas mais inclusivas e focalizadas para a eliminação e não apenas suavização de disparidades e segregações.

DETERMINATION OF THE CHANGE OF THE DESIGN POSITION OF THE PROFILE OF THE BELT CONVEYOR ON THE LOAD OF THE ROLLER BEARINGS

The article attempts to establish the basic patterns in the formation of loads in the structure of the conveyor frame due to changes in the design position of the constituent elements based on analytical calculations. The amortization replacement of rollers and the establishment of a change in the projected resource caused the change in the design position.The aim of the work is to study the interaction of the elements of the belt conveyor on the convex region of the profile when the design position changes and to determine the change in the resource of the roller support elements. The purpose of the work is formulated from the analysis of unplanned stops and premature replacement of conveyor elements, in particular conveyor rollers, on the convex region of the profile.To achieve this goal the influence of the geometric parameters of the convex section of the belt conveyor profile on the force interaction of the belt and roller supports was considered, and the change in the resource of the roller bearings was determined.To characterize the geometric parameters of the convex section of the belt conveyor, the following were selected: the number of roller supports, the distance between the roller supports, the radius of curvature of the conveyor profile, the angle of the curved section. The mathematical model is based on the belt equilibrium equation, which contains the tension forces of the conveyor belt and the forces from the action of roller supports. Particular attention is paid to establishing the effect of changing the geometric parameters of the convex section on the roller bearing life. It has been established that a decrease in the radius of the transitional convex section as a result of a change in the initial design position by 2.4 times leads to an increase in the force acting on the roller support by 161%. It was found that the increase in force is the reason for the rapid exit from the operational state of the rolling bearings of the roller bearings, as evidenced by the intensive drop in the resource of the rollers (18 times).The proposed algorithm for determining the main parameters of the force interaction of the elements of the belt conveyor on the convex region of the profile will make it possible to predict the resource and prevent the conveyor from leaving the premature operational state.

Fabrication of gold-silver bimetal nanoparticles/silicon nanoporous pillar array substrate and surface-enhanced Raman scattering detection

A novel gold-silver/silicon nanoporous pillar array substrate was prepared by a droplet-confined deposition technique and a replacement reaction method. Its surface-enhanced Raman scattering behaviors to R6G were studied. The substrate has not only high detection sensitivity, but also good signal uniformity and stability. The SERS detection limit is down to 10–13 M. The enhancement factor is 2.9 × 105 and the maximal relative standard deviation is only 9.2% at 10–7 M R6G. Moreover, it has a well stability with a slight drop in the spectrum intensity after placed for 35 days in air. This work suggested that the novel substrate has a potential application in environmental detection.

Zero-thermal-quenching and improved chemical stability of a UCr4C4-type phosphor via crystal site engineering

• CsNa 2 K(Li 3 SiO 4 ) 4 :Ce 3+ phosphor was synthesized with 80% quantum efficiency. • First zero-thermal-quenching phosphor among other Ce 3+ -doped phosphors. • Upon Ce 3+ doping in host shows excellent chemical stability than Eu 2+ doping. • CsNa 2 K(Li 3 SiO 4 ) 4 :Ce 3+ shows high color rendering index value of 95 at 1000 mA. Europium-doped UCr 4 C 4 cuboid phosphors with narrow and tunable emission show promise for application in designing light-emitting diodes with high color purity and thermal stability. Nevertheless, their poor chemical stability bottlenecks their use in lighting applications. Herein, a dual narrow-band blue-emitting Ce 3+ -doped CsNa 2 K(Li 3 SiO 4 ) 4 (CNKLSO) cuboid phosphor with a quantum yield of 80% is synthesized. The dual-band emission is attributed to the occupation of Ce 3+ at two distinct sites of CNKLSO, which is consistent with the density functional theory outcomes. Ce 3+ doping produces stable emission characteristics, in contrast to Eu 2+ incorporation, because of the improved site stability, as realized from bond valence sum calculations. Remarkably, no drop in the emission intensity is observed even at 200 °C, making CNKLSO:Ce 3+ the first Ce 3+ -based zero-thermal-quenching phosphor. A CNKLSO:Ce 3+ -based white light-emitting diode displays an excellent color rendering index (~95) at a high flux current of 1000 mA. The proposed study indicates that Ce 3+ doping in other UCr 4 C 4 - type oxide phosphors may improve the site stability, which in turn the chemical stability of the phosphor materials can be boosted.

The active environment influence on the luminescence of SnO2 nanoparticles’ ensembles in a porous matrix

The environmental influence (with alkaline and acid components) on the luminescence character of SnO2 nanoparticles’ ensembles in a porous silicate glass matrix was studied. The established changes in the luminescence are associated with the interaction nature of alkaline or acid ions with nanoparticles in the pores of silicate glass. A sharp drop in the radiation intensity is due to the formation of unstable ammonia complexes SnO2[NH3] in the alkaline environmental with a large capture cross section. Such complexes are not formed in an acidic environmental, and a slow and smooth change in the photoluminescence intensity is associated with the penetration of HCl molecules into the pores with subsequent dissociation. A correlation was also established between the changes in luminescence behavior and the composition of the initial solution for the porous matrix impregnation. The possibility of spontaneous restoration of the initial characteristics of the investigated material is established. This and its almost absolute chemical resistance make it possible to use an ensemble of SnO2 nanoparticles in silicate porous glass as an active working material for a luminescent ammonia sensor.

Synthesis of Porous Proton Ion Conducting Solid Polymer Blend Electrolytes Based on PVA: CS Polymers: Structural, Morphological and Electrochemical Properties.

In this study, porous cationic hydrogen (H+) conducting polymer blend electrolytes with an amorphous structure were prepared using a casting technique. Poly(vinyl alcohol) (PVA), chitosan (CS), and NH4SCN were used as raw materials. The peak broadening and drop in intensity of the X-ray diffraction (XRD) pattern of the electrolyte systems established the growth of the amorphous phase. The porous structure is associated with the amorphous nature, which was visualized through the field-emission scanning electron microscope (FESEM) images. The enhancement of DC ionic conductivity with increasing salt content was observed up to 40 wt.% of the added salt. The dielectric and electric modulus results were helpful in understanding the ionic conductivity behavior. The transfer number measurement (TNM) technique was used to determine the ion (tion) and electron (telec) transference numbers. The high electrochemical stability up to 2.25 V was recorded using the linear sweep voltammetry (LSV) technique.

Time-Resolved Fluorescence Microscopy Combined with Scanning Electrochemical Microscopy: A New Way to Visualize Photo-Induced Electron Transfer Quenching with an Electrofluorochromic Probe

The combination of Scanning Electrochemical Microscopy (SECM) and Time-Resolved Fluorescence Microscopy was successfully implemented to investigate the control of the fluorescence of a tetrazine derivative in solution according to its redox state, a phenomenon called electrofluorochromism. The normalized fluorescence intensity difference between the 'on' and 'off' states can be tuned by the tip potential and the distance between the polarized tip and the substrate. It is demonstrated for the first time that luminescence lifetime can be modulated as well, an evidence that a quenching process contributes to the fluorescence intensity drop. The experimental results demonstrate that this quenching is due to the electron transfer reaction between the excited fluorophore and the electrogenerated anion radical. A mixed dynamic and static quenching mechanism is considered to fit the variations of both luminescence intensity and lifetime ratios vs. the coulombic charge. The pertinence of a static quenching is validated by DFT calculations. Insulating (glass) and conductive (ITO) substrates have been tested and optical approach curves based on fluorescence lifetime modulation have been obtained in each case that are more sensitive than the electrochemical one based on the tip current. Finally, numerical simulations have been performed to fit these optical approach curves and validate the role of the electron transfer quenching in the variation of fluorescence intensity and lifetime.

Scale dependence of textural alignment in shales quantified using electron microscopy

Textural alignment is the primary cause of anisotropy associated with the permeability and mechanical and acoustic properties of rocks. Although particle alignment in shales is known to be influenced by burial depth, mineralogical composition, and diagenetic history, understanding how these influence image-based measures of compaction at the micrometer to nanometer scale is not well understood. Here, we use a novel method, which combines scanning electron microscopy and image analysis algorithms, to quantify clay alignment in sedimentary rocks. For a given field of view, the alignment intensity in shales from the Podhale Basin in Poland is positively correlated with clay content based on image analysis. However, our analysis also shows that the intensity is strongly dependent on the spatial scale of imaging: as magnification increases and the field of view in the SEM images decreases, the alignment intensity drops. Therefore, in images with small fields of view, clay alignment is determined by the presence of localized equant silicate mineral grains, which effectively hinder the alignment process at the micrometer scale. By contrast, in images with larger fields of view, alignment intensity is determined by the overall compaction state. We also show that when the field of view is constant, alignment intensity decreases with pixel density, and we suggest a range of operating parameters required for obtaining optimum values for alignment intensity from SEM images of shales.

Lensless, reflection-based dark-field microscopy (RDFM) on a CMOS chip.

We present for the first time a lens-free, oblique illumination imaging platform for on-sensor dark- field microscopy and shadow-based 3D object measurements. It consists of an LED point source that illuminates a 5-megapixel, 1.4 µm pixel size, back-illuminated CMOS sensor at angles between 0° and 90°. Analytes (polystyrene beads, microorganisms, and cells) were placed and imaged directly onto the sensor. The spatial resolution of this imaging system is limited by the pixel size (∼1.4 µm) over the whole area of the sensor (3.6×2.73 mm). We demonstrated two imaging modalities: (i) shadow imaging for estimation of 3D object dimensions (on polystyrene beads and microorganisms) when the illumination angle is between 0° and 85°, and (ii) dark-field imaging, at >85° illumination angles. In dark-field mode, a 3-4 times drop in background intensity and contrast reversal similar to traditional dark-field imaging was observed, due to larger reflection intensities at those angles. With this modality, we were able to detect and analyze morphological features of bacteria and single-celled algae clusters.