Tilt Angle Data Research Articles

DETERMINATION OF TILT AND AZIMUTH ANGLES OF SOLAR PANELS AT TANJUNGPURA UNIVERSITY SOLAR POWER PLANT USING PVSYST 7.3 SOFTWARE SIMULATION

Solar Power Plant is a plant that uses solar energy as a renewable source and converts solar energy into electrical energy. To maximize the intensity of sunlight, solar panels need an optimal tilt angle to receive high sunlight intensity. This research aims to determine the optimal tilt angle of solar panels and azimuthal angle so that solar panels obtain maximum output energy. The type of solar panel used is the monocrystalline type with an installed power of 1.51 MW with a total of 2800 panels using a nominal panel power of 540 Wp and 12 units of 1.1 kW inverters. At the research location, Tanjungpura University Solar Power Plant with coordinates 0°3'37.486" LU 109°20'34.633" BT (-0.060410, 109.342969). With a simulation method using PVsyst software to determine the optimal tilt angle and solar radiation data on meteonorm 8.1 in PVsyst software. The results showed that the optimal panel tilt angle and azimuth angle in producing maximum output energy at Tanjungpura University Solar Power Plant is at a panel angle of 5° with the azimuth angle facing northeast (-45°) with an output energy of 2365 MWh/year, specific production of 1564 kWh/kW/year, and normalized production of 4.29 kWh/kWp/day.

Study on the Behavior of Saturated Cardanol-Based Surfactants at the Crude Oil/Water Interface through Molecular Dynamics Simulations.

Cardanol is a green biosurfactant with broad application prospects, which is expected to be used to enhance oil recovery (EOR). This paper designed two types of surfactants (extended and nonextended), including six kinds of nonionic and anion-nonionic surfactants. The position changes of PO and EO chains and the effects of different hydrophilic groups on the interface properties were studied with molecular dynamics simulations by constructing a model of crude oil (containing four components) and water molecules. The results of interfacial tension and solvent-accessible surface area showed that the interfacial properties of sulfate were better than those of sulfonates and nonionic surfactants. Meanwhile, the interface properties of nonextended surfactants were better than those of extended surfactants. The gyration radius (Rg) and tilt angle data demonstrated that when EO chains were located between hydrophobic groups and PO chains (nonextended surfactants), the adsorption capacity of surfactants at crude oil and water interfaces could be effectively improved. The radial distribution function of the hydrophilic group and hydrophobic group of surfactants with water molecules and four components of the crude oil molecule, respectively, explained that surfactants (8EO8POSO4) had better emulsification performance when the intermolecular interactions between crude oil and water two phases were relatively balanced. This study provides a theoretical reference for the design of oil-displacement surfactants and the mechanism analysis of emulsification properties.

Application of Machine Learning Technology for Automatic Motion Recognition for Japanese Tea-Making Procedure of CHA-NO-YU

CHA-NO-YU, the Japanese traditional tea-making ceremony, has been a research subject in many academic fields including anthropology, psychology, and engineering. To effectively study the CHA-NO-YU, automatic recognition of motions of the tea-making procedure is desirable. Hence, herein, a method is proposed to recognize 12 motion classes of the tea-making procedure with acceleration, angular velocity, and right-hand tilt angle data. In the experiment, one Japanese subject with 18 years of experience in CHA-NO-YU performed the 12 motion classes repeatedly, and a 99-sensor dataset was obtained for every motion class. In the recognition step, random forest classifier was adopted. Finally, the recognition of the 12 motion classes of the tea-making procedure could be realized with greater than 0.98 accuracy, precision, recall, and F1-score

Eigenspectra of solar active region long-period oscillations

Context. We studied the low-frequency ≲0.5 h−1 (long-period ≳2 h) oscillations of active regions (ARs). The investigation is based on an analysis of a time series built from Solar Dynamics Observatory/Helioseismic and Magnetic Imager photospheric magnetograms and comprises case studies of several types of AR structures. Aims. The main goals are to investigate whether ARs can be engaged in long-period oscillations as unified oscillatory entities and, if so, to determine the spectral pattern of such oscillations. Methods. Time series of characteristic parameters of the ARs, such as, the total area, total unsigned radial magnetic flux, and tilt angle, were measured and recorded using the image moment method. The power spectra were built out of Gaussian-apodised and zero-padded datasets. Results. There are long-period oscillations ranging from 2 to 20 h, similarly to the characteristic lifetimes of super-granulation, determined from the datasets of the AR total area and radial magnetic flux, respectively. However, no periodicity in tilt angle data was found. Conclusions. Whatever nature these oscillations have, they must be energetically supported by convective motions beneath the solar surface. The possible interpretations can be related to different types of magnetohydrodynamic oscillations of the multi-scale structure of the AR magnetic field, which is probably linked with the characteristic turnover timescales of the super-granulation cells. The presence of oscillations in the radial magnetic flux data may be connected to periodic flux emergence or cancellation processes.

Sunspot tilt angles revisited: Dependence on the solar cycle strength

Context. The tilt angle of sunspot groups is crucial in the Babcock-Leighton (BL) type dynamo for the generation of the poloidal magnetic field. Some studies have shown that the tilt coefficient, which excludes the latitudinal dependence of the tilt angles, is anti-correlated with the cycle strength. If the anti-correlation exists, it will be shown to act as an effective nonlinearity of the BL-type dynamo to modulate the solar cycle. However, some studies have shown that the anti-correlation has no statistical significance. Aims. We aim to investigate the causes behind the controversial results of tilt angle studies and to establish whether the tilt coefficient is indeed anti-correlated with the cycle strength. Methods. We first analyzed the tilt angles from Debrecen Photoheliographic Database (DPD). Based on the methods applied in previous studies, we took two criteria (with or without angular separation constraint Δs > 2.​​°5) to select the data, along with the linear and square-root functions to describe Joy’s law, and three methods (normalization, binned fitting, and unbinned fitting) to derive the tilt coefficients for cycles 21–24. This allowed us to evaluate different methods based on comparisons of the differences among the tilt coefficients and the tilt coefficient uncertainties. Then we utilized Monte Carlo experiments to verify the results. Finally, we extended these methods to analyze the separate hemispheric DPD data and the tilt angle data from Kodaikanal and Mount Wilson. Results. The tilt angles exhibit an extremely wide scatter due to both the intrinsic mechanism for its generation and measurement errors, for instance, the unipolar regions included in data sets. Different methods to deal with the uncertainties are mainly responsible for the controversial character of the previous results. The linear fit to the tilt-latitude relation of sunspot groups with Δs > 2.​​°5 of a cycle carried out without binning the data can minimize the effect of the tilt scatter on the uncertainty of the tilt coefficient. Based on this method the tilt angle coefficient is anti-correlated with the cycle strength with strong statistical significance (r = −0.85 at 99% confidence level). Furthermore, we find that tilts tend to be more saturated at high latitudes for stronger cycles. The tilts tend to show a linear dependence on the latitudes for weak cycles and a square-root dependence for strong cycles. Conclusions. This study disentangles the cycle dependence of sunspot group tilt angles from the previous results that were shown to be controversial, spurring confusion in the field.

Single-Event Response of 22-nm Fully Depleted Silicon-on-Insulator Static Random Access Memory

We are presenting single-event effect testing results on a 22-nm fully depleted silicon-on-insulator test chip from GlobalFoundries. The 128-Mb static random access memory (SRAMs) were irradiated with heavy ions, and the results are compared to previous partially depleted technology generations (32 and 45 nm). The per-bit cross section is approximately an order of magnitude lower than the previous generations with a higher onset linear energy transfer (LET). No dependence on roll angle or input pattern was found. Tilt angle data follow the cosine law. Increasing the SRAM array supply voltage from the minimum tested 0.73 V to the maximum 1.08 V decreases SEE sensitivity by as much as 8%. Decreasing the p-well voltage from the nominal 0 V to the maximum -2 V increases the SEE cross section by as much as 2×. The n-well voltage has little effect on the SEE sensitivity due to the specifics of the transistor layout in the SRAM. Changing both the n- and p-well voltages simultaneously results in identical results as when only the p-well voltage was changed.

Development of a voiding diary using urination recognition technology in mobile environment

We invented a wearable device that can measure voiding time and frequency by checking a habitual series of characteristic motions among men. This study collected and analyzed urination time data collected smart bands worn by patients to resolve the clinical issues posed by using voiding charts. By developing a smart band-based algorithm for assessing urination time in patients, this study aimed to explore the feasibility of urination management systems. This study aimed to assess urination time based on a patient’s posture and changes in posture. Motion data were obtained from a smart band on the arm. An algorithm that identifies the three stages of urination (forward movement, urination, backward movement) was developed based on data collected from a 3-axis accelerometer and tilt angle data. Therefore, we analyze hidden Markov model (HMM)-based sequential data to determine urination time. Real-time data were acquired from the smart band. For data corresponding to a specific duration, the value of the signals was calculated and then compared with the set analysis model to calculate the time of urination. The final accuracy of the algorithm was calculated based on clinical guidelines for urologists. The experiment showed a high average accuracy of 92.5%, proving the robustness of the proposed algorithm. The proposed urination time recognition technology draws on acceleration data and tilt angle data collected via a smart band; these data were then analyzed using a classifier after applying the HMM method.

Liquid holdup and pressure drop in packed column with structured packing under offshore conditions

In this study, we propose liquid holdup and pressure drop models for a packed column with structured packing, under offshore conditions. To improve the model performance, we conducted experiments for an air-water system under various conditions (i.e., liquid load, gas load, and permanent tilt angle). We used a column with an inner diameter of 0.6 m and a packed height of 4 m, which was installed on a sloshing machine that enabled us to simulate offshore conditions, and corrected the key parameters of the model based on the experimental data obtained. The result showed that in offshore column design, the rolling motion can be regarded as permanent tilt, by extracting the tilt angle data from the rolling motion characteristics.

Personalized Urination Activity Recognition Based on a Recurrent Neural Network Using Smart Band.

PurposeThough it is very important obtaining exact data about patients’ voiding patterns for managing voiding dysfunction, actual practice is very difficult and cumbersome. In this study, data about urination time and interval measured by smart band device on patients’ wrist were collected and analyzed to resolve the clinical arguments about the efficacy of voiding diary. By developing a smart band based algorithm for recognition of complex and serial pattern of motion, this study aimed to explore the feasibility of measurement the urination time and intervals for voiding dysfunction management.MethodsWe designed a device capable of recognizing urination time and intervals based on specific postures of the patient and consistent changes in posture. These motion data were obtained by a smart band worn on the wrist. An algorithm that recognizes the repetitive and common 3-step behavior for urination (forward movement, urination, backward movement) was devised based on the movement and tilt angle data collected from a 3-axis accelerometer. The sequence of body movements during voiding has consistent temporal characteristics, so we used a recurrent neural network and long short-term memory based framework to analyze the sequential data and to recognize urination time. Real-time data were acquired from the smart band, and for data corresponding to a certain duration, the value of the signals was calculated and then compared with the set analysis model to calculate the time of urination. A comparative study was conducted between real voiding and device-detected voiding to assess the performance of the proposed recognition technology.ResultsThe accuracy of the algorithm was calculated based on clinical guidelines established by urologists. The accuracy of this detecting device was high (up to 94.2%), proving the robustness of the proposed algorithm.ConclusionsThis urination behavior recognition technology showed high accuracy and could be applied in clinical settings to characterize patients’ voiding patterns. As wearable devices are developed and generalized, algorithms detecting consistent sequential body movement patterns reflecting specific physiologic behavior might be a new methodology for studying human physiologic behavior.

Development of Personalized Urination Recognition Technology Using Smart Bands

PurposeThis study collected and analyzed activity data sensed through smart bands worn by patients in order to resolve the clinical issues posed by using voiding charts. By developing a smart band-based algorithm for recognizing urination activity in patients, this study aimed to explore the feasibility of urination monitoring systems.MethodsThis study aimed to develop an algorithm that recognizes urination based on a patient’s posture and changes in posture. Motion data was obtained from a smart band on the arm. An algorithm that recognizes the 3 stages of urination (forward movement, urination, backward movement) was developed based on data collected from a 3-axis accelerometer and from tilt angle data. Real-time data were acquired from the smart band, and for data corresponding to a certain duration, the absolute value of the signals was calculated and then compared with the set threshold value to determine the occurrence of vibration signals. In feature extraction, the most essential information describing each pattern was identified after analyzing the characteristics of the data. The results of the feature extraction process were sorted using a classifier to detect urination.ResultsAn experiment was carried out to assess the performance of the recognition technology proposed in this study. The final accuracy of the algorithm was calculated based on clinical guidelines for urologists. The experiment showed a high average accuracy of 90.4%, proving the robustness of the proposed algorithm.ConclusionsThe proposed urination recognition technology draws on acceleration data and tilt angle data collected via a smart band; these data were then analyzed using a classifier after comparative analyses with standardized feature patterns.

추적이 가능한 쿼드로터 호버링 시스템 구현

쿼드로터는 일반 무인항공기와 달리 구조가 단순하고 그 활용 가치가 매우 높아 많은 사람들의 관심을 받고 있다. 하지만 드론에 대한 관심이 높아짐에 따라 항공 안전사고 또는 분실에 대비한 비행체의 안정성과 위치파악의 중요성이 대두되고 있다. 따라서 본 논문에서는 쿼드로터의 모델링을 수식적으로 유도하여 이를 선형화시켜 간단한 제어기로 모델을 안정화시키고 다양한 센서로부터 얻은 데이터를 필터를 거쳐 기울어진 정도를 파악하여 보다 안정한 호버링이 가능한 추적 시스템을 제안하였다. 개발된 추적시스템은 비행 중인 쿼드로터의 위치를 컴퓨터로 전송해 이를 경로로 나타내어 비행경로를 파악할 수 있고 비행속도, 고도 등의 다양한 정보를 동시에 확인할 수 있게 하였다. 그리고 실제 쿼드로터에 사용되는 센서는 외란과 진동에 의해 정확한 센서 값을 측정할 수 없기 때문에 칼만필터와 상보필터를 통한 센서 결합으로 이를 극복하여 쿼드로터 호버링의 안정성을 PID 제어를 통해 구현하였다. 이를 모의 실험을 통하여 쿼드로터의 속도, 위치, 고도 등의 다양한 정보를 실시간으로 확인하였다. Unlike general unmanned aerial vehicles, the quad-rotor is attracting the attention of many people because of simple structure and very useful value. However, as the interest in drones increases, the safety and location of vehicles are becoming more important provide against aviation safety accidents or lost accidents. Therefore, in this paper, we propose a tracking system that stabilizes the model with a simple controller by linearized modeling and grasp tilt angle data from various sensor through the filter. The developed tracking system transmits the position of the quad-rotor in flight to the computer and shows it through the route, so it can check the flight path and various information such as flight speed and altitude at the same time. Then the sensor used in the actual quad-rotor can not measure exact sensor data for disturbance and vibration. So we use sensor fusion of Kalman filter and Complementary filter to overcome this problem and the stability of the quad-rotor hovering is realized by PID control. Through simulation, various information such as the speed, position, and altitude of the quad-rotor were confirmed in real time.

Flame characteristics and burning rate of small pool fires under downslope and upslope oblique winds

This paper presents an experimental investigation on burning rate, flame tilt angle and flame length of small ethanol pool fires under different oblique winds. Square pool fires with dimension of 4cm and 6cm with wind attack angles from 0° to 30° and wind speeds from 0 to 3.28ms−1 for downslope airflow and from 0 to 1.90ms−1 for upslope airflow are tested. Flame tilt angle and flame length are determined based on luminous flame intermittency from the flame images. The results show that the burning rate under downslope wind is relatively larger than that under upslope wind at the same absolute wind speed and slope angle. The flame tilt angle and flame length generally increase with the increase of wind slope angle for downslope airflow, but decrease with the increase of upslope airflow angle. At a given wind slope angle, the flame tilt angle generally increases with the increase of wind speed until to an asymptotic value when the wind speed exceeds 0.35ms−1; the flame length first increases and then decreases for downslope wind, but initially decreases then increases before decrease again for upslope wind. In addition, some modified correlations are developed to analyze the flame tilt angle and flame length data under oblique wind conditions.

Sunspot areas and tilt angles for solar cycles 7–10

Extending the knowledge about the properties of solar cycles into the past is essential for understanding the solar dynamo. This paper aims at estimating areas of sunspots observed by Schwabe in 1825-1867 and at calculating the tilt angles of sunspot groups. The sunspot sizes in Schwabe's drawings are not to scale and need to be converted into physical sunspot areas. We employed a statistical approach assuming that the area distribution of sunspots was the same in the 19th century as it was in the 20th century. Umbral areas for about 130,000 sunspots observed by Schwabe were obtained, as well as the tilt angles of sunspot groups assuming them to be bipolar. There is, of course, no polarity information in the observations. The annually averaged sunspot areas correlate reasonably with sunspot number. We derived an average tilt angle by attempting to exclude unipolar groups with a minimum separation of the two alleged polarities and an outlier rejection method which follows the evolution of each group and detects the moment it turns unipolar at its decay. As a result, the tilt angles, although displaying considerable scatter, place the leading polarity on average 5.85+-0.25 closer to the equator, in good agreement with tilt angles obtained from 20th-century data sets. Sources of uncertainties in the tilt angle determination are discussed and need to be addressed whenever different data sets are combined. The sunspot area and tilt angle data are provided online.

Comparison of Debrecen and Mount Wilson/Kodaikanal sunspot group tilt angles and the Joy's law

The study of active region tilt angles and their variations in different time-scales plays an important role in revealing the subsurface dynamics of magnetic flux ropes and in understanding the dynamo mechanism. In order to reveal the exact characteristics of tilt angles, precise long-term tilt angle data bases are needed. However, there are only a few different data sets at present, which are difficult to be compared and cross-calibrate because of their substantial deviations. In this paper, we describe new tilt angle data bases derived from the Debrecen Photoheliographic Data (DPD) (1974–) and from the SOHO/MDI-Debrecen Data (SDD) (1996–2010) sunspot catalogues. We compare them with the traditional sunspot group tilt angle data bases of Mount Wilson Observatory (1917–85) and Kodaikanal Solar Observatory (1906–87) and we analyse the deviations. Various methods and filters are investigated which may improve the sample of data and may help in deriving better results based on combined data. As a demonstration of the enhanced quality of the improved data set a refined diagram of Joy's law is presented.

EFFECTS OF THE SCATTER IN SUNSPOT GROUP TILT ANGLES ON THE LARGE-SCALE MAGNETIC FIELD AT THE SOLAR SURFACE

The tilt angles of sunspot groups represent the poloidal field source in Babcock-Leighton-type models of the solar dynamo and are crucial for the build-up and reversals of the polar fields in Surface Flux Transport (SFT) simulations. The evolution of the polar field is a consequence of Hale's polarity rules, together with the tilt angle distribution which has a systematic component (Joy's law) and a random component (tilt-angle scatter). We determine the scatter using the observed tilt angle data and study the effects of this scatter on the evolution of the solar surface field using SFT simulations with flux input based upon the recorded sunspot groups. The tilt angle scatter is described in our simulations by a random component according to the observed distributions for different ranges of sunspot group size (total umbral area). By performing simulations with a number of different realizations of the scatter we study the effect of the tilt angle scatter on the global magnetic field, especially on the evolution of the axial dipole moment. The average axial dipole moment at the end of cycle 17 (a medium-amplitude cycle) from our simulations was 2.73G. The tilt angle scatter leads to an uncertainty of 0.78 G (standard deviation). We also considered cycle 14 (a weak cycle) and cycle 19 (a strong cycle) and show that the standard deviation of the axial dipole moment is similar for all three cycles. The uncertainty mainly results from the big sunspot groups which emerge near the equator. In the framework of Babcock-Leighton dynamo models, the tilt angle scatter therefore constitutes a significant random factor in the cycle-to-cycle amplitude variability, which strongly limits the predictability of solar activity.

Sunspot group tilt angles and the strength of the solar cycle (Corrigendum)

Context. It is well known that the tilt angles of active regions increase with their latitude (Joy’s law). It has never been checked before, however, whether the average tilt angles change from one cycle to the next. Flux transport models show the importance of tilt angles for the reversal and build up of magnetic flux at the poles, which is in turn correlated to the strength of the next cycle. Aims. Here we analyse time series of tilt angle measurements and look for a possible relationship of the tilt angles with other solar cycle parameters, in order to glean information on the solar dynamo and to estimate their potential for predicting solar activity. Methods. We employed tilt angle data from Mount Wilson and Kodaikanal observatories covering solar cycles 15 to 21. We analyse the latitudinal distribution of the tilt angles (Joy’s law), their variation from cycle to cycle, and their relationship to other solar cycle parameters, such as the strength (or total area covered by sunspots in a cycle), amplitude, and length. Results. The two main results of our analysis follow. 1. We find an anti-correlation between the mean normalised tilt angle of a given cycle and the strength (or amplitude) of that cycle, with a correlation coefficient of rc = −0.95 (99.9% confidence level) and rc = −0.93 (99.76% confidence level) for Mount Wilson and Kodaikanal data, respectively. 2. The product of the cycle’s averaged tilt angle and the strength of the same cycle displays a significant correlation with the strength of the next cycle (rc = 0.65 at 89% confidence level and rc = 0.70 at 92% confidence level for Mount Wilson and Kodaikanal data, respectively). An even better correlation is obtained between the source term of the poloidal flux in Babcock-Leighton-type dynamos (which contains the tilt angle) and the amplitude of the next cycle. Further we confirm the linear relationship (Joy’s law) between the tilt angle and latitude with slopes of 0.26 and 0.28 for Mount Wilson and Kodaikanal data, respectively. In addition, we obtain good positive correlations between the normalised-areaweighted tilt angle and the length of the following cycle, whereas the strength or the amplitude of the next cycle does not appear to be correlated to the tilt angles of the current cycle alone. Conclusions. The results of this study indicate that, in combination with the cycle strength, the active region tilt angles play an important role in building up the polar fields at cycle minimum.

A new mathematical quantification of wind-blown flame tilt angle of hydrocarbon pool fires with a new global correlation model

A new mathematical methodology is brought forward in this paper to objectively quantify the flame tilt angle based on flame appearance intermittency spatial distribution obtained from the flame images series recorded in the experiments, in counteracting the uncertainty in traditional method due to the fact of extensive vibration nature of the flame in a wind. The flame tilt angle is determined based on a proposed sum function of the product of multiplication of p(x, y) as probability of flame appearance at each pixel, by D(x, y) as perpendicular distance from the pixel to a threshold line originated from the flame base center. The flame tilt angle is solved mathematically as the angle of the threshold line when the above sum function at the two sides of the threshold line in the flame intermittency distribution contour are early equal. Experiments are carried out for ethanol and heptane square pool fires with dimensions of 10cm, 15cm, 20cm and 25cm in wind speed of 0–2.5m/s. The tilt angles of the flames in the experiments determined by above mathematical method are compared with previous models reported in the literatures. A new dimensionless global parameter, equating the wind speed by a characteristic uprising velocity of the flame supported by the buoyancy strength of the pool fire, is further proposed, which is shown to better converge and correlate the flame tilt angle data than previous models.

Birefringence suppression near the smectic A–smectic C phase transition in de Vries-type liquid crystals

Two smectic liquid crystal materials exhibiting a de Vries-type smectic A to smectic C transition with low layer shrinkage were studied using polarised microscopy. Birefringence and tilt angle was measured as a function of temperature using a novel camera and software system. The analysis showed unusual features in birefringence, which had a peak within the smectic A phase and decreased significantly with cooling for a ˜15°C range above the smectic A–smectic C transition in both materials. The reduction in birefringence above the smectic A–smectic C transition was interpreted with a critical fluctuation model, which allowed calculation of the heat capacity critical exponent α. Exponents were not in a clear universality class, similar to previously reported results on other non-de Vries materials. However, a recently published mean field model for de Vries smectics provided an alternate explanation for birefringence suppression. Five analyses were performed on the birefringence and tilt angle data and were interpreted using new predictions of this mean field model. Our results for the observed reduced temperature range , where T is temperature and TC is the smectic A–smectic C transition temperature, were consistent with all mean field theory predictions for a transition near or at a tricritical point.

Thermally controlled optical shutter in an inter-molecular hydrogen bonded liquid crystal

Novel homologs series of supra-molecular liquid crystals have been isolated. Hydrogen bond is formed between mandelic acid (MD) and various homologs of p- n-alkyloxy benzoic acids (nOBA) and has been confirmed by FTIR studies. Optical polarizing microscopic observations show that all these materials exhibit rich liquid crystallinity with various mesophases. Phase transition temperatures and enthalpy values are experimentally evaluated by DSC studies and the phase diagram of homologous series has been constructed. An interesting feature is the observation of thermally controlled reversible optical shuttering action in one of the homolog, wherein with the increment of temperature the homeotropic texture changes to homogenous texture of smectic F. Thus, this optical shuttering phenomenon is reversible. Optical tilt angle data of two homologs have been fitted to power law equation and it is found that the mean field theory prediction is valid. The light intensity profile in homeotropic region of smectic F in one complex has been experimentally analyzed and a steep sudden decrement of the intensity of light manifesting the distortion of the molecular alignment is experimentally found.

Study of Self Assembly Systems Formed by Malic Acid and Alkyloxy Benzoic Acids

Self assembly systems formed by malic acid and alkyloxy benzoic acids are characterized. The ferroelectric ingredient malic acid formed double hydrogen bond with p-n-alkyloxy benzoic acids. Various hydrogen bonded complexes have been synthesized with malic acid and pentyl to dodecyloxy benzoic acid, respectively. Fourier transformation infrared (FTIR) studies confirm the hydrogen bond formation. Polarizing optical microscopic (POM) studies revealed the textural information while the transition and enthalpy values are calculated from differential scanning calorimetry (DSC) studies. A phase diagram has been constructed from the POMand DSC studies. A new smectic ordering, smectic X*, has been identified which exhibits a finger print type texture. This phase has been characterized by POM, DSC, helix, and tilt angle studies. The transition from traditional cholesteric to smectic X* phase is observed to be first order. The tilt angle data in this phase has been fitted to a power law and the temperature variation of the tilt angle follows mean field theory predictions. The results of FTIR, POM, DSC, tilt angle, and helicoidal studies are discussed.