Retention Power Research Articles

Preparation and characterization of biomaterial for phosphate ion removal: Kinetics, isotherms and thermodynamics studies

Phosphate ions are among the pollutants that pose a major risk to the environment and human health at high concentrations. The aim of this article is to evaluate the elimination capacity of these ions of the Carpobrotus edulis plant in its raw state and treated with (HCl, 0.5 M). Both biomaterials were characterized by scanning electron microscopy coupled to an energy dispersive X-ray spectrometer (SEM-EDS), Fourier transform infrared spectroscopy (FT-IR), differential thermal analysis (DTA), and thermal gravimetric analysis (TGA). Retention power depends on several parameters, such as adsorbent mass, contact time, initial concentration, pH, and temperature. The acid treatment allows a reduction in soluble organic matter characterized by a decrease in BOD5 and COD of 30% and 70% respectively. For a fixed ratio of the order of 3.75 g.L−1 and an initial concentration of 1000 mg.L−1, phosphate ion removal percentages exceed 90%. The kinetics fit well with the pseudo-second-order model, and the results show strong agreement with the Langmuir isotherm. The maximum adsorption capacity of phosphate ions is 380.95 mg.g−1 for the plant native and 888.89 mg.g−1 in the modified state. The thermodynamics of adsorption are spontaneous and exothermic for plant native and endothermic for plant treated.

The effect of mnemonics method on students’ retention and learning outcomes in the learning of biology

The mnemonic method is one of the procedures that is considered effective for improving students’ learning outcomes and memory. This study aims to examine the effectiveness of the mnemonics methods in improving students' retention and learning outcomes in Biology class on the System of Biological Classifications. The pre-experimental method with one group of pre-test and post-test design was applied in this study. Thirty students of a secondary school in Pontianak were used as research samples taken by using intact group random sampling. The learning outcomes test used was 20 multiple-choice questions with four options having a validity level of 0.86 and a reliability of 0.87. Based on the data analysis, it was concluded: (1) the average learning outcomes before treatment was 48.50 and after treatment was 72.50; (2) the differences in the average student learning outcomes before treatment was = 48.50 and after treatment was = 72.50 (t = 5.517, p <0.05); (3) the level of increase in retention power after treatment of R = 0.85.06% is high. It is recommended that Science-Biology teachers apply mnemonics in a varied and sustainable manner to make it more useful and according to the content of the teaching material to be taught.

Gel microextraction from hydrophilic paint layers: A comparison between Agar-gel and Nanorestore Gel® HWR for spectroscopic identification of madder

While non-invasive analyses are widespread for the study of inorganic components in cultural heritage, the identification of organic substances can be very challenging when sampling is forbidden. In particular, organic dyes are hardly detectable because of their low concentration and tendency to fade. Hydrogels retention and release properties make them suitable for microextraction of dyes directly from the artifact, maintaining its integrity. After extraction, the hydrogels versatility makes them ideal for a multi-analytical study of the dyes. In this work, the gel microextraction procedure was put to the test of hydrophilic paint layers. Different Agar-gel weight concentrations were tested and compared with Nanorestore Gel® High Water Retention for the extraction of madder dyes from Arabic gum paint layers. UV–vis spectroscopy and SER spectroscopy were effective in identifying the analytes. Nonetheless, the sampling mechanism and the procedure invasiveness have proved to be dependent on the hydrogels retention power.

Temperature Variation Operation of Mixed-VT 3T GC-eDRAM for Low Power Applications in 2Kbit Memory Array

Embedded memories were once utilized to transfer information between the CPU and the main memory. The cache storage in most traditional computers was static-random-access-memory (SRAM). Other memory technologies, such as embedded dynamic random-access memory (eDRAM) and spin-transfer-torque random-access memory (STT-RAM), have also been used to store cache data. The SRAM, on the other hand, has a low density and severe leakage issues, and the STT-RAM has high latency and energy consumption when writing. The gain-cell eDRAM (GC-eDRAM), which has a higher density, lower leakage, logic compatibility, and is appropriate for two-port operations, is an attractive option. To speed up data retrieval from the main memory, future processors will require larger and faster-embedded memories. Area overhead, power overhead, and speed performance are all issues with the existing architecture. A unique mixed-V T 3T GC-eDRAM architecture is suggested in this paper to improve data retention times (DRT) and performance for better energy efficiency in embedded memories. The GC-eDRAM is simulated using a standard complementary-metal-oxide-semiconductor (CMOS) with a 130nm technology node transistor. The performance of a 2kbit mixed-VT 3T GC-eDRAM array were evaluated through corner process simulations. Each memory block is designed and simulated using Mentor Graphics Software. The array, which is based on the suggested bit-cell, has been successfully operated at 400MHz under a 1V supply and takes up almost 60-75% less space than 6T SRAM using the same technology. When compared to the existing 6T and 4T ULP SRAMs(others' work in K. Sharma et al.and A. Goyal et al.)the retention power of the proposed GC-eDRAM is around 80-90% lower.

IMPACT OF INTERNATIONAL WEB SERIES –MONEY HEIST ON THE YOUTH OF GUJARAT REGION

In the era of digital cinema, web series is the revolutionary audio-visual format. They introduced us to Over-The-Top, Video-On-Demand binge-watching. Moreover, international OTT platforms like Netflix, Amazon prime video, HBO max, and Disney+ have started to produce their premium and original content with the aim to grow their reach in every possible country; it created lots of opportunities for new filmmakers and production houses. Money Heist is the best suitable example of a journey from flop to success. After the relaunch and distribution in the essential international without advertising catalogue by Netflix, it became a huge success. It got the third rank among the most-watched popular web series globally. This study focuses on the Money Heist’s audience behaviour pattern, the impact of the series, its characters, and retention power towards the young cohort of the Gujarat region. This research was conducted with the empirical quantitative method; the researcher used the convenience sampling technique for sample collection. The results solved all the research questions with an adequate positive approach. Distinctive characteristics of the Money heist web series made it a top-rated, addictive, and popular show that became local to global to again local.

Synthesis of a New Chelating Iminophosphorane Derivative (Phosphazene) for U(VI) Recovery.

A new synthetic chelating N–hydroxy–N–trioctyl iminophosphorane (HTIP) was prepared through the reaction of trioctylphosphine oxide (TOPO) with N–hydroxylamine hydrochloride in the presence of a Lewis acid (AlCl3). Specifications for the HTIP chelating ligand were successfully determined using many analytical techniques, 13C–NMR, 1H–NMR, FTIR, EDX, and GC–MS analyses, which assured a reasonable synthesis of the HTIP ligand. The ability of HTIP to retain U(VI) ions was investigated. The optimum experimental factors, pH value, experimental time, initial U(VI) ion concentration, HTIP dosage, ambient temperature, and eluents, were attained with solvent extraction techniques. The utmost retention capacity of HTIP/CHCl3 was 247.5 mg/g; it was achieved at pH = 3.0, 25 °C, with 30 min of shaking and 0.99 × 10−3 mol/L. From the stoichiometric calculations, approximately 1.5 hydrogen atoms are released during the extraction at pH 3.0, and 4.0 moles of HTIP ligand were responsible for chelation of one mole of uranyl ions. According to kinetic studies, the pseudo–first order model accurately predicted the kinetics of U(VI) extraction by HTIP ligand with a retention power of 245.47 mg/g. The thermodynamic parameters ΔS°, ΔH°, and ΔG° were also calculated; the extraction process was predicted as an exothermic, spontaneous, and advantageous extraction at low temperatures. As the temperature increased, the value of ∆G° increased. The elution of uranium ions from the loaded HTIP/CHCl3 was achieved using 2.0 mol of H2SO4 with a 99.0% efficiency rate. Finally, the extended variables were used to obtain a uranium concentrate (Na2U2O7, Y.C) with a uranium grade of 69.93% and purity of 93.24%.

A 1‐GHz GC‐eDRAM in 7‐nm FinFET with static retention time at 700 mV for ultra‐low power on‐chip memory applications

AbstractConventional static random‐access memory (SRAM) suffers from high leakage power in advanced complementary metal‐oxide‐semiconductor nodes. Meanwhile, gain‐cell embedded dynamic random‐access memory (GC‐eDRAM) is an area‐efficient alternative to SRAM, although it requires periodic refresh cycles. In this regard, this study proposes a fin field‐effect transistor (FinFET)‐based 5T GC‐eDRAM bitcell that addresses the leakage power issue of SRAM while avoiding the bandwidth‐consuming refreshes of GC‐eDRAM. Furthermore, for the feasibility of scaling down transistors, the gain‐cell design is based on the FinFET, which overcomes short‐channel problems. The proposed 5T bitcell provides additional internal feedback relative to the 4T all‐nMOS fully depleted‐silicon on insulator (FD‐SOI) gain cell to ensure the static retention of both “1” and “0” data. The 2‐kB array was simulated by employing a 7‐nm FinFET predictive technology model (PTM) using HSPICE. The simulation results show that the proposed 5T bitcell (at 0.7 V) enables over 13× smaller data retention power and 10× area reduction compared to the 4T all‐nMOS GC‐eDRAM cell in a 28‐nm FD‐SOI technology.

Biomechanical Influences on Mesh-Related Complications in Incisional Hernia Repair.

Aim: Hernia repair strengthens the abdominal wall with a textile mesh. Recurrence and pain indicate weak bonds between mesh and tissue. It remains a question which biomechanical factors strengthen the mesh-tissue interface, and whether surgeons can enhance the bond between mesh and tissue.Material and Methods: This study assessed the strength of the mesh-tissue interface by dynamic loads. A self-built bench test delivered dynamic impacts. The test simulated coughing. Porcine and bovine tissue were used for the bench test. Tissue quality, mesh adhesiveness, and fixation intensity influenced the retention power. The influences were condensed in a formula to assess the durability of the repair. The formula was applied to clinical work. The relative strength of reconstruction was related to the individual human abdominal wall. From computerized tomography at rest and during Valsalva's Maneuver, the tissue quality of the individual patient was determined before surgery.Results: The results showed that biomechanical parameters observed in porcine, bovine, and human tissue were in the same range. Tissues failed in distinct patterns. Sutures slackened or burst at vulnerable points. Both the load duration and the peak load increased destruction. Stress concentrations elevated failure rates. Regional areas of force contortions increased stress concentrations. Hernia repair improved strain levels. Measures for improvement included the closure of the defect, use of higher dynamic intermittent strain (DIS) class meshes, increased mesh overlap, and additional fixation. Surgeons chose the safety margin of the reconstruction as desired.Conclusion: The tissue quality has now been introduced into the concept of a critical and a gained resistance toward pressure-related impacts. A durable hernia repair could be designed from available coefficients. Using biomechanical principles, surgeons could minimize pain levels. Mesh-related complications such as hernia recurrence can potentially be avoided in incisional hernia repair.

COMPARATIVE CLINICAL EVALUATION ON THE EFFECT OF GUDUCHI VATI AND YASTIMADHU VATI ON MEDHA (ACADEMIC PERFORMANCE) IN SCHOOL GOING CHILDREN

Medha is a concept in Ayurveda where man has always failed to arrive at a definite conclusion. As per the ayurvedic classics, Medha is the retention power of an individual or is the unobstructed and uninterrupted perception and retention of knowledge in all the aspects of an object [1] Academic Performance of an individual is an outcome of his mental and physical potential. Recent studies show that the intellectual abilities of students have a positive association with their scholastic achievement.[2] Acharya Charaka has mentioned 4 individual drugs under Chara- koktha Medhya Rasayanas for their action on Medha [3] and Guduchi Swarasa and Yastimadhu Ksheerapaka are mentioned among them. In this study, an attempt was made to evaluate the Medhya effect of Guduchi Vati and Yastimadhu Vati. The study was a comparative clinical study with a total subject of 40, where 20 patients were administered with Guduchi Vati and the other 20 with Yastimadhu Vati. The study showed a statistically significant result where the Guduchi Vati is having similar action to that of Yastimadhu Vati on Medha (Academic Perfor- mance) in School going children. Keywords: Guduchi Vati, Yastimadhu Vati, Medha, Academic Performance

A New Physical Design Flow for a Selective State Retention Based Approach

This research presents a novel approach for physical design implementation aimed for a System on Chip (SoC) based on Selective State Retention techniques. Leakage current has become a dominant factor in Very Large Scale Integration (VLSI) design. Power Gating (PG) techniques were first developed to mitigate these leakage currents, but they result in longer SoC wake-up periods due to loss of state. The common State Retention Power Gating (SRPG) approach was developed to overcome the PG technique’s loss of state drawback. However, SRPG resulted in a costly expense of die area overhead due to the additional state retention logic required to keep the design state when power is gated. Moreover, the physical design implementation of SRPG presents additional wiring due to the extra power supply network and power-gating controls for the state retention logic. This results in increased implementation complexity for the physical design tools, and therefore increases runtime and limits the ability to handle large designs. Recently published works on Selective State Retention Power Gating (SSRPG) techniques allow reducing the total amount of retention logic and their leakage currents. Although the SSRPG approach mitigates the overhead area and power limitations of the conventional SRPG technique, still both SRPG and SSRPG approaches require a similar extra power grid network for the retention cells, and the effect of the selective approach on the complexity of the physical design has not been yet investigated. Therefore, this paper introduces further analysis of the physical design flow for the SSRPG design, which is required for optimal cell placement and power grid allocation. This significantly increases the potential routing area, which directly improves the convergence time of the Place and Route tools.

Obtaining jute fabrics with enhanced sorption properties and “closing the loop” of their lifecycle

The objective of this investigation was to obtain jute fabrics with enhanced sorption properties (by using simple and cost-effective alkali and oxidative modifications) and a long life cycle. The applied alkali modifications lead to hemicellulose removal and decreased the fibers’ crystallinity, both contributing to enhanced fibers’ sorption properties, i.e., water retention power and degree of fibers’ swelling up to 49 % and 70 %, respectively. A connection between cellulose polymorphs’ (cellulose I and cellulose II) contents (determined by XRD), fibers’ surface morphology (verified by FESEM), fabrics’ crimp, and capillarity of jute fabrics modified with 17.5 % NaOH was established. During the oxidative modifications, significant changes in jute fibers’ chemical composition and structure (i.e., lignin removal and more homogeneous middle lamellae) occurred which further resulted in enhanced jute fabrics’ water retention power and capillarity as well as fibers’ swelling up to 80 %, 75 %, and 54 %, compared to the raw jute, respectively. In order to move towards a circular economy and to ensure the recycling and re-use of recycled fabrics, the jute fabrics with enhanced sorption properties were evaluated as biosorbents for anthraquinone dye C. I. Acid Blue 111. The obtained results revealed that the jute fabrics’ maximum biosorption capacities for this dye ranged from 12.94 to 18.97 mg/g, while the equilibrium adsorption data were highly consistent with the Langmuir isotherm model. Moreover, based on the predicted dye pKa values, the fabric zeta potential, content of carboxyl and aldehyde groups as well as hydrogen bond intensity (determined by ATR-FTIR), a possible mechanism of the dye biosorption onto jute fabric waste was proposed.

Enhancing Memory Skills of Autism Spectrum Disorder Children using Gamification

Sharp memory of growing children is important for education and learning of any new skills. Learning new languages is an important aspect for all children. Kids with Autism Spectrum Disorder (ASD) need extra attention to enhance the memory skills. ASD is a developmental issue that influences communication and social conduct. It leads to the slow development of certain skills in children. The reasons for ASD are yet to obscure; however, it is normal in children having parents of higher age groups. Individuals with ASD generally avoid social communications, lack confidence in the eye to eye contact, fiddle a great deal, and regularly experience the ill effects of other issues like ADHD, OCD, etc.They tend to get distracted very easily. They are often obsessive about particular things and ignorant or indifferent about everything else. ASD does not include mental retardation (MR). Even though individuals experiencing ASD are improper at conveying, they sometimes have a better than average IQ. In this paper, a memory-enhancing mobile game has been designed that would help ASD children to improve the memory and help increase the stock of words that would eventually help in communication skills. The proposed mobile game would help Children diagnose with ASD to increase their memory retention power and help parents’ track their progress using gamification concepts.

Gain-Cell Embedded DRAM Under Cryogenic Operation—A First Study

Operating circuits under cryogenic conditions is effective for a large spectrum of applications. However, the refrigeration requirement for the cooling of cryogenic systems introduces serious issues in terms of power dissipation. Gain-cell embedded dynamic random access memory (GC-eDRAM) is a low-area, logic-compatible embedded memory alternative to static random access memory (SRAM), which has the potential to provide ultralow-power operation under cryogenic conditions due to the lower leakages at these temperatures. In this article, we present the first comparative design exploration of GC-eDRAM under cryogenic conditions performed with transistor models characterized based on actual silicon measurements under temperatures as low as 77 K. Our study shows that the two-transistor (2T)-based GC-eDRAM configurations turn out to be the best solutions for very low-temperature operation. In particular, the 2T mixed GC-eDRAM configurations allow read sensing margin improvements (up to 99%) within the 2T-based configurations while at the same time excel in terms of data retention time (+44%) and power consumption (-27%) when compared to more complex GC-eDRAM topologies. Moreover, even better improvements in terms of area (-73%), leakage power (-97%), retention power (-76%), and energy (-66%) are observed when compared to conventional 6T-SRAM.

A Comparative Study to Understand the Efficiency of two Behavioral Change Communication Models Against Plastic Use

The word pollution when comes to the mind feels dirty but people never think about how the surroundings are being polluted. If people want to get a clear environment, the behavioral change should be the first stepping stone. It is known to all that plastic is a non-biodegradable material but when talks about easily accessible material, mass production of plastic has been continued. Though different steps have been taken to ban the use of this harmful material every time failure has been observed. In this situation, behavioral change communication may help to solve this problem. Keeping all in the mind this particular study was conducted by two researchers in a particular block called Egra which is situated in West Bengal, India to understand the efficiency of the two models. Two different models have been applied viz. M1 and M2 and both work through a total of 6 stages. A total of 50 samples were taken and it was divided into two groups 25 each through the lottery method and applied the respective models. Through the study it has been observed that at the beginning periods success of the M1 model was good when 88% of people of M1 reach the contemplation period, another side only 52 percent of people reach the contemplation period of the M2 model. But slowly with time M2 also started to gear up and at the last, it achieves the same achievement as M1. This data proves that the M2 model is slow but steady. In the last stage, it was found that for M1 number of people in the contemplation period has increased to 60 percent people in the action and maintenance also decreased to 28 and 4 percent. Where in the case of M2 the people who are in action are 20 percent, 60 percent in the maintenance stage, and 20 percent population is terminated from this habit. In this stage, it is clear that the M2 has quite well retention power than the M1. Above all, it can be said that even M2 is slow though it is a better model than M1. Because at the end of the day it brings more numbers of terminated people. Later in the future by amalgamating these two models small weaknesses can be resolved, but for that, another detailed study has to be done.

POLIFOSFATO DE AMÔNIO E SUPERFOSFATOSIMPLES EM CULTIVARES DE FEIJÃO COMUM

Phosphorus is the most limiting nutrient in bean cultivation, however this nutrient is low absorbed by the high soil retention power with this nutrient. Thus, studies with sources, doses and cultivars are important to improve the productivity of this culture. Given the above, this work aimed to evaluate five common bean cultivars submitted to phosphorus levels with simple superphosphate and ammonium polyphosphate. The experimental design used was in randomized blocks in a 5x2x2 factorial arrangement with five cultivars: (Uirapuru, Tuiuiu, Tangara, Estilo and Splendor); two sources of phosphorus (Simple Superphosphate and Ammonium Polyphosphate); two levels of fertilization (high and medium), with the medium dose with single superphosphate being 50 mg P.kg -1 of soil and the high dose with 200 mg P.kg -1. The cultivars showed genetic variability for productivity, mass of 100 grains and height of insertion of the first pod and the dose of 200 mg P.kg -1 of soil improved most characteristics of the bean.

Gamification for Learning Media: Learning Chemistry with Games Based on Smartphone

This research aims to determine the effectiveness of smartphone-based games as a media for learning chemistry, especially hydrocarbons. The effectiveness obtained from the activities of learners, learner questionnaire, learning outcomes, power retention of the learning outcomes of students, and motivation questionnaire. The study was conducted at a high school in East Java Indonesia with one experimental class and one control class. The results of the study showed the activities of the students 90.47%, the student questionnaire 85.5% - 98.2%, learning outcomes achieve classical mastery 86.6%, the retention power of learning outcomes in the excellent category, and the student motivation questionnaire gave a percentage of 88.89% to 93.33%. Based on the results, then the game is based smartphone effectively used as a media of learning chemistry on hydrocarbon material. The advantages gained in a game that is able to eliminate the boredom learners when studying chemistry and makes power retention of the results of learning is high.

SleepRunner: A 28-nm FDSOI ULP Cortex-M0 MCU With ULL SRAM and UFBR PVT Compensation for 2.6–3.6-μW/DMIPS 40–80-MHz Active Mode and 131-nW/kB Fully Retentive Deep-Sleep Mode

Preventing device obsolescence in Internet-of-things (IoT) is mandatory for its massive deployment to be ecologically sustainable. This calls for ultralow-power (ULP) reprogrammable microcontroller units (MCUs) for long lifetime, yet with sufficient computing performance to extract the meaningful information from the sensed data before transmitting it to the cloud. In this article, we present the SleepRunner MCU with logic/memory/power management co-optimization for best exploitation of the forward back biasing (FBB) capability in fully-depleted silicon-on-insulator (FDSOI) technologies. For low active power, we use ultralow-voltage (ULV) low- V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> logic with upsized gate length and asymmetric FBB, a ULP SRAM macro with low read-access energy and switched-capacitor voltage regulators (SCVRs) for ULV supply generation from a single I/O voltage. The custom ULP SRAM macro is based on an ultralow-leakage (ULL) FBB-compatible bitcell for low SRAM retention power. In addition, a dual-loop digital unified frequency/back-bias regulation (UFBR) system efficiently compensates process and temperature variations with short wakeup from the zero-back-bias deep-sleep mode. Performance is measured for a synthetic benchmark and biomedical inference applications. The measured 40-MHz 2.6- μW/DMIPS (3.3 μW/MHz) active and 131-nW/kB deep-sleep power consumptions with CPU state retention are respectively 3 × and 2.5 × lower than for a conventional MCU design in this technology. This demonstrates the interest of 28-nm FDSOI with the proposed FBB-driven system optimization for ULP MCUs.

Revitalizing the Concept of Vocabulary Teaching in Professional Education

The vocabulary of the English language is compartmentalized in professional degree courses like Engineering, Medical, Law, Pharmaceutical, Arts etc. Due to this the professionals are unable to express themselves convincingly. In due course of the time they become handicapped to use the universal vocabulary related to the field of others and building the gap between industry and academia. The industry is in need of the professionals who can speak to the globe. Because of this limited vocabulary, as the authors are working in the professional colleges observed, that there is a miserable failure when a general topic is given to express. Though the professionals are good at academics fail to express their thought process in an open forum due to lack of vocabulary. It is also observed that the so-called examination system will examine their retention power instead of testing their general ability. The academia on the other hand will not concentrate on universal vocabulary since it is pestered with curriculum and syllabus design. The aspiring students who want to go abroad are struggling to get through the Basic English tests. Since the Common European Framework Reference (CEFR) put some standards in the English language proficiency levels to be recognized globally, the professionals understood the importance of expression. Here exactly the professionals face the building blocks. Though the professionals selected through campus recruitments, feel difficulty to communicate effectively. To reason, the reasons are many to speak on. Hence, the paper is going to address the challenges involved in.

Affective state and learning environment based analysis of students’ performance in online assessment

Online learning and assessments have become an integral part of education systems around the world. Online education and learning stand out as one of the important applications of cognitive computing where artificial intelligence - based models can be built by taking into account cognitive abilities of the students such as working memory, retention power, reasoning skills etc. The systems used for online assessment can be better designed considering some factors effecting learning environments and cognitive abilities of the learners. These factors such as sleep hours, time of the day, noise level, environment settings and mood etc. are closely linked with his/ her cognitive skills and affective state which in turn may effect performance in online assessment. This paper attempts to identify the effect of mood, sleep hours, time of the day and energy level on the performance of engineering students in an online assessment in India. The students have attempted the test on Moodle (2.9.0) in three sessions in a day viz. morning, afternoon and late afternoon. Sleep hours and energy level have been captured using a set of questions embedded within the online test items. Mood has been captured by the pictorial representation of various moods using robotic characters during the test. One -way ANOVA has been used as statistical measure to test various hypotheses. The study reported that sleep hours and perceived energy level during various times of the day had no significant effect on the performance of students. However, mood and time of the day had an impact on the students’ performance. Higher number of students performed the best in the morning hours of the day. Also, students with positive moods performed better than students who reported negative mood. The findings from this study can be used for designing a framework of an adaptive tutor based on cognitive skills for teaching different subjects to students.

Benefiting From State Dependencies in Asymmetric SRAM Cells Through Conditional Word-Flipping

This brief presents an approach that dynamically exploits content dependencies in asymmetric memory cells. By using a capacitive, logic-value majority circuit and an extra column of memory cells, words are conditionally flipped during write operations to reach the more beneficial state for storage. A 1-kb SRAM block of low-voltage memory cells was implemented and manufactured in a 130-nm CMOS. The memory cells were made writable and read-stable at low supply voltages with a single-ended write and single-ended read structure using six multithreshold transistors that give rise to an asymmetric retention power. At a supply voltage of 350 mV, the content-dependent leakage power in the asymmetric memory cell is 23 times smaller when storing logic “1”s compared with logic “0”s. A derived statistical model suggests that the mean, wordwise, static power savings of the word-flipping scheme become 15.70% for 8-bit words of uniform bit probability. For the implemented SRAM macro, the mean improvement for the retention power is, including flip logic and decoder and driver overheads, found to be 14.69%. In boundary tests, by writing all words full of undesired values, the power saving becomes 80.37%, while writing all words full of desired values causes a power penalty of 6.14%. Measurement results confirm the improvement in retention power with a ten-chip mean improvement of 11.93% for the same data set.