Search

Conversion of producer gas tar without coke generation is a great challenge. This study investigates conversion of tar model benzene using different configurations of highly non-porous ɣ-Al2O3 packed bed reactor at 1000–1100 0C. The configurations comprised of different positions (relative to top (P1), center (P2) and bottom (P3) of reactor furnace), heights (5, 13 and 25 cm) and particles sizes (0.5, 3 and 5 mm) of alumina packed bed. Steam and CO2 were used as reforming media for tested benzene concentrations (0.4–1.8 vol%). The results showed benzene conversions of 48–91% with negligible steady thin coke generation using a packed bed (height: 25 cm, particles size: 3 mm) at P1. Whereas, relative high benzene conversions of 63–93 and 68–95% at P2 and P3 respectively with unsteady thick coke generation at benzene concentrations greater than 0.4 vol% increased differential upstream pressures (DUPs) of beds. Similar unsteady coke generation at benzene concentrations greater than 0.8 vol% and temperature of 1100 0C was observed with packed beds of heights of 5 and 13 cm, and particles size of 0.5 mm at P1. Generation of unsteady coke with condensed structure as evidenced by its characterization was attributable to increased benzene polymerization and reduced bed surface gasification reactions due to improperly installed packed bed. Developed kinetic model predicted well the generated coke. As conclusion, properly installed alumina packed bed pertaining to tar concentration and other experimental conditions may inhibit coke generation during tar conversion. more...

Conversion of producer gas tar without coke generation is a great challenge. This study investigates conversion of tar model benzene using different configurations of highly non-porous ɣ-Al2O3 packed bed reactor at 1000–1100 0C. The configurations comprised of different positions (relative to top (P1), center (P2) and bottom (P3) of reactor furnace), heights (5, 13 and 25 cm) and particles sizes (0.5, 3 and 5 mm) of alumina packed bed. Steam and CO2 were used as reforming media for tested benzene concentrations (0.4–1.8 vol%). The results showed benzene conversions of 48–91% with negligible steady thin coke generation using a packed bed (height: 25 cm, particles size: 3 mm) at P1. Whereas, relative high benzene conversions of 63–93 and 68–95% at P2 and P3 respectively with unsteady thick coke generation at benzene concentrations greater than 0.4 vol% increased differential upstream pressures (DUPs) of beds. Similar unsteady coke generation at benzene concentrations greater than 0.8 vol% and temperature of 1100 0C was observed with packed beds of heights of 5 and 13 cm, and particles size of 0.5 mm at P1. Generation of unsteady coke with condensed structure as evidenced by its characterization was attributable to increased benzene polymerization and reduced bed surface gasification reactions due to improperly installed packed bed. Developed kinetic model predicted well the generated coke. As conclusion, properly installed alumina packed bed pertaining to tar concentration and other experimental conditions may inhibit coke generation during tar conversion. more...

Conversion of producer gas tar without coke generation is a great challenge. This study investigates conversion of tar model benzene using different configurations of highly non-porous ɣ-Al2O3 packed bed reactor at 1000–1100 0C. The configurations comprised of different positions (relative to top (P1), center (P2) and bottom (P3) of reactor furnace), heights (5, 13 and 25 cm) and particles sizes (0.5, 3 and 5 mm) of alumina packed bed. Steam and CO2 were used as reforming media for tested benzene concentrations (0.4–1.8 vol%). The results showed benzene conversions of 48–91% with negligible steady thin coke generation using a packed bed (height: 25 cm, particles size: 3 mm) at P1. Whereas, relative high benzene conversions of 63–93 and 68–95% at P2 and P3 respectively with unsteady thick coke generation at benzene concentrations greater than 0.4 vol% increased differential upstream pressures (DUPs) of beds. Similar unsteady coke generation at benzene concentrations greater than 0.8 vol% and temperature of 1100 0C was observed with packed beds of heights of 5 and 13 cm, and particles size of 0.5 mm at P1. Generation of unsteady coke with condensed structure as evidenced by its characterization was attributable to increased benzene polymerization and reduced bed surface gasification reactions due to improperly installed packed bed. Developed kinetic model predicted well the generated coke. As conclusion, properly installed alumina packed bed pertaining to tar concentration and other experimental conditions may inhibit coke generation during tar conversion. more...

Conversion of producer gas tar without coke generation is a great challenge. This study investigates conversion of tar model benzene using different configurations of highly non-porous ɣ-Al2O3 packed bed reactor at 1000–1100 0C. The configurations comprised of different positions (relative to top (P1), center (P2) and bottom (P3) of reactor furnace), heights (5, 13 and 25 cm) and particles sizes (0.5, 3 and 5 mm) of alumina packed bed. Steam and CO2 were used as reforming media for tested benzene concentrations (0.4–1.8 vol%). The results showed benzene conversions of 48–91% with negligible steady thin coke generation using a packed bed (height: 25 cm, particles size: 3 mm) at P1. Whereas, relative high benzene conversions of 63–93 and 68–95% at P2 and P3 respectively with unsteady thick coke generation at benzene concentrations greater than 0.4 vol% increased differential upstream pressures (DUPs) of beds. Similar unsteady coke generation at benzene concentrations greater than 0.8 vol% and temperature of 1100 0C was observed with packed beds of heights of 5 and 13 cm, and particles size of 0.5 mm at P1. Generation of unsteady coke with condensed structure as evidenced by its characterization was attributable to increased benzene polymerization and reduced bed surface gasification reactions due to improperly installed packed bed. Developed kinetic model predicted well the generated coke. As conclusion, properly installed alumina packed bed pertaining to tar concentration and other experimental conditions may inhibit coke generation during tar conversion. more...

Conversion of producer gas tar without coke generation is a great challenge. This study investigates conversion of tar model benzene using different configurations of highly non-porous ɣ-Al2O3 packed bed reactor at 1000–1100 0C. The configurations comprised of different positions (relative to top (P1), center (P2) and bottom (P3) of reactor furnace), heights (5, 13 and 25 cm) and particles sizes (0.5, 3 and 5 mm) of alumina packed bed. Steam and CO2 were used as reforming media for tested benzene concentrations (0.4–1.8 vol%). The results showed benzene conversions of 48–91% with negligible steady thin coke generation using a packed bed (height: 25 cm, particles size: 3 mm) at P1. Whereas, relative high benzene conversions of 63–93 and 68–95% at P2 and P3 respectively with unsteady thick coke generation at benzene concentrations greater than 0.4 vol% increased differential upstream pressures (DUPs) of beds. Similar unsteady coke generation at benzene concentrations greater than 0.8 vol% and temperature of 1100 0C was observed with packed beds of heights of 5 and 13 cm, and particles size of 0.5 mm at P1. Generation of unsteady coke with condensed structure as evidenced by its characterization was attributable to increased benzene polymerization and reduced bed surface gasification reactions due to improperly installed packed bed. Developed kinetic model predicted well the generated coke. As conclusion, properly installed alumina packed bed pertaining to tar concentration and other experimental conditions may inhibit coke generation during tar conversion. more...

Strawberry is nutritious but perishable, and it is susceptible to quality flaws and infections after harvest. Objective: To examine strawberry biochemical changes with harvest maturity and preservation methods. Methods: The experiment was factorial with a completely randomized design (CRD). Strawberry cv. Chandler fruit was harvested at three color-based maturation phases (M1: 0% red, M2: 50% red, and M3: 100% red), frozen, and freeze-dried and analyzed for quality. Total soluble solids (TSS), titratable acidity (TA), vitamin C, total phenolic content (TPC), total antioxidant capacity, SOD, POD, CAT, and organoleptic characteristics were assessed for quality. Results: Due to harvest maturity, completely ripe strawberries displayed higher biochemical properties such as total soluble solids (TSS), titratable acidity (TA), and TSS/TA than 50% and 0% of red strawberries. 100% red strawberries also had greater TPC and POD. Compared to strawberries picked during the green stage (0% red color), strawberries harvested at 100% and 50% red color had better aroma, color, and flavor. TSS, TSS/TA, Vitamin C, antioxidants, total phenolic content, and peroxidase were better in freeze-dried strawberries than frozen strawberries. Conclusions: The superior fruit aroma and color rating made frozen strawberries more popular than freeze-dried ones. The preserved fruit retained these qualities better for 7 months in dried storage. This study found that strawberry fruit should be harvested at 100% red and freeze-dried for commercial use. more...

This study investigates the conversion of benzene in a novel highly non-porous ɣ-Al2O3 packed bed reactor at 1000–1100 °C. The influences of packed bed presence, reforming medium (steam and CO2), gas flow rate and benzene concentration on steady state benzene conversion are examined. In presence of packed bed, benzene conversions of 52, 75, and 84% were achieved with combined steam and CO2 reforming at 1000, 1050, and 1100 °C, respectively. Whereas, benzene conversion of 65% without the packed bed at 1000 °C experienced a continuous increase in differential upstream pressure (DUP) of high temperature (HT) filter at reactor downstream due to deposition of in situ generated coke. High concentrations of generated CO and H2 of 2.3 and 6 vol% with packed bed than 1.4 and 4.7 vol% without the packed respectively, were achieved. CO2 reforming achieved high benzene conversions of 68–98% than 42–80% achieved with stream reforming at packed bed reactor temperatures of 1000–1100 °C. The results indicated that presence of ɣ-Al2O3 packed bed with possible surface reactions directed the conversion of benzene to combustible gases instead of coke. Hence, ɣ-Al2O3 packed bed reactor could be a suitable choice for coke-free conversion of tar of gasifier producer gas. more...

This study investigates the conversion of benzene in a novel highly non-porous ɣ-Al2O3 packed bed reactor at 1000–1100 °C. The influences of packed bed presence, reforming medium (steam and CO2), gas flow rate and benzene concentration on steady state benzene conversion are examined. In presence of packed bed, benzene conversions of 52, 75, and 84% were achieved with combined steam and CO2 reforming at 1000, 1050, and 1100 °C, respectively. Whereas, benzene conversion of 65% without the packed bed at 1000 °C experienced a continuous increase in differential upstream pressure (DUP) of high temperature (HT) filter at reactor downstream due to deposition of in situ generated coke. High concentrations of generated CO and H2 of 2.3 and 6 vol% with packed bed than 1.4 and 4.7 vol% without the packed respectively, were achieved. CO2 reforming achieved high benzene conversions of 68–98% than 42–80% achieved with stream reforming at packed bed reactor temperatures of 1000–1100 °C. The results indicated that presence of ɣ-Al2O3 packed bed with possible surface reactions directed the conversion of benzene to combustible gases instead of coke. Hence, ɣ-Al2O3 packed bed reactor could be a suitable choice for coke-free conversion of tar of gasifier producer gas. more...

This study investigates the conversion of benzene in a novel highly non-porous ɣ-Al2O3 packed bed reactor at 1000–1100 °C. The influences of packed bed presence, reforming medium (steam and CO2), gas flow rate and benzene concentration on steady state benzene conversion are examined. In presence of packed bed, benzene conversions of 52, 75, and 84% were achieved with combined steam and CO2 reforming at 1000, 1050, and 1100 °C, respectively. Whereas, benzene conversion of 65% without the packed bed at 1000 °C experienced a continuous increase in differential upstream pressure (DUP) of high temperature (HT) filter at reactor downstream due to deposition of in situ generated coke. High concentrations of generated CO and H2 of 2.3 and 6 vol% with packed bed than 1.4 and 4.7 vol% without the packed respectively, were achieved. CO2 reforming achieved high benzene conversions of 68–98% than 42–80% achieved with stream reforming at packed bed reactor temperatures of 1000–1100 °C. The results indicated that presence of ɣ-Al2O3 packed bed with possible surface reactions directed the conversion of benzene to combustible gases instead of coke. Hence, ɣ-Al2O3 packed bed reactor could be a suitable choice for coke-free conversion of tar of gasifier producer gas. more...

The intensified burning of fossil fuels and the discharging of industrial wastes are severe threats to the environment. The released CO2 and organic fractions of industrial and municipal wastes exacerbate global warming. Converting the released CO2 and organic wastes into beneficial electricity and biofuel-chemicals is deemed an environmental necessity. Microbial electrosynthesis (MES) presents a promising technology for bio-electrochemical conversion of released CO2 and organic wastes into electricity and biofuel-chemicals using external-powered and/or self-powered microbial oxidation/reduction processes. The MES system consists of anodic and cathodic processes. The technology mostly relies on the capacity of electron transfer from electroactive biofilm to the electrode for reducing organics into value-added chemicals and sustaining their respiration and growth. The current review aims to summarize and explore the diversified application of electrogenic microbes and their metabolic pathways of electron transfer. It also summarizes the MES reactor design and operational parameters that influence the catalysis of biofilm and hence, the system performance. The review concludes with a critical evaluation of technical challenges that should be overcome before large-scale implementation. Furthermore, various recommendations on technical perspectives for successful implementation and application, including future research directions, are presented in this study. more...

This study investigates the conversion of benzene in a novel highly non-porous ɣ-Al2O3 packed bed reactor at 1000–1100 °C. The influences of packed bed presence, reforming medium (steam and CO2), gas flow rate and benzene concentration on steady state benzene conversion are examined. In presence of packed bed, benzene conversions of 52, 75, and 84% were achieved with combined steam and CO2 reforming at 1000, 1050, and 1100 °C, respectively. Whereas, benzene conversion of 65% without the packed bed at 1000 °C experienced a continuous increase in differential upstream pressure (DUP) of high temperature (HT) filter at reactor downstream due to deposition of in situ generated coke. High concentrations of generated CO and H2 of 2.3 and 6 vol% with packed bed than 1.4 and 4.7 vol% without the packed respectively, were achieved. CO2 reforming achieved high benzene conversions of 68–98% than 42–80% achieved with stream reforming at packed bed reactor temperatures of 1000–1100 °C. The results indicated that presence of ɣ-Al2O3 packed bed with possible surface reactions directed the conversion of benzene to combustible gases instead of coke. Hence, ɣ-Al2O3 packed bed reactor could be a suitable choice for coke-free conversion of tar of gasifier producer gas. more...

This study investigates the conversion of benzene in a novel highly non-porous ɣ-Al2O3 packed bed reactor at 1000–1100 °C. The influences of packed bed presence, reforming medium (steam and CO2), gas flow rate and benzene concentration on steady state benzene conversion are examined. In presence of packed bed, benzene conversions of 52, 75, and 84% were achieved with combined steam and CO2 reforming at 1000, 1050, and 1100 °C, respectively. Whereas, benzene conversion of 65% without the packed bed at 1000 °C experienced a continuous increase in differential upstream pressure (DUP) of high temperature (HT) filter at reactor downstream due to deposition of in situ generated coke. High concentrations of generated CO and H2 of 2.3 and 6 vol% with packed bed than 1.4 and 4.7 vol% without the packed respectively, were achieved. CO2 reforming achieved high benzene conversions of 68–98% than 42–80% achieved with stream reforming at packed bed reactor temperatures of 1000–1100 °C. The results indicated that presence of ɣ-Al2O3 packed bed with possible surface reactions directed the conversion of benzene to combustible gases instead of coke. Hence, ɣ-Al2O3 packed bed reactor could be a suitable choice for coke-free conversion of tar of gasifier producer gas. more...

The use of fossil fuels has caused an ongoing increase in greenhouse gases (GHGs), which have a negative impact on both the environment and human health. The world requires an alternative green sustainable fuel that can solve these problems. Hydrogen (H2) can be considered as an alternative green energy source as it has zero carbon emissions. Methane (CH4) decomposition is a potential technique to produce H2 fuel. Gliding arc discharge (GAD) reactors have gained significant attention to produce H2 from the decomposition of CH4. This review focuses on the application of GAD reactors for CH4 conversion. The effects of different parameters, such as operation conditions, additives, geometric configuration, and catalysts, on the performance of the GAD reactor, are discussed in this review. more...

Twenty years after the initial culture of HP, there has been a substantial change in the finding and treatment of upper gastroduodenal disease. A growing number of stomach cancers are caused by Helicobacter pylori infection, and researchers are also looking into how this infection affects other upper gastric tract inflammation. There has been significant progress in our understanding of the pathogenesis of this infection. Although there are powerful anti-microbial medications on the market, there is still no perfect treatment and the therapeutic indications are constantly evolving. Following the discovery of an HP infection, the clinician assesses the patient's clinical condition to determine whether therapy is necessary. Typically, HP eradication is suggested for the treatment and prevention of the infection. The microorganism that is introduced into the human stomach cancer that develops in the gastrointestinal tract causes the HP disease. In addition to gastrointestinal issues like belching, bloating, vomiting, indigestion, and constipation, it has been used for a long time to treat a variety of disorders. The purpose of the current study's findings was to assess how supplementing with ginger powder affected patients who had the HP infection's eradication and the relief of their dyspeptic symptoms. more...

Detection of benign and malignant liver masses is very important for the treatment. Objectives: To determine the diagnostic accuracy of ultrasound for hepatic masses taking computed tomography as gold standard Methods: It was cross a sectional analytical study to.it involves 266 patients suffering from hepatocellular cell carcinoma age group 45 to 65 years visiting Department of Radiology THQ Hospital Hazro, both genders were included. Consecutive sampling method was used. The collection of data was done through questionnaire and analysis by using SPSS version 25. Results: This study enlisted the participation of 261 patients. The average age of all patients was 59.28 14 years, with a range of 45 to 65 years. It describes that the total number of true positive disease were 228 which was also detected on ultrasound. However, the occurrence of HCC is highest on CT scan when compared with adenoma and hemangioma. There were 28 patients with multiple lesions, with 71.4 % being malignant and 28.6 % being benign. On the other hand, 22 individuals had a single lesion, of which 36.4% were malignant and 63.6 % were benign (p 0.001). CT had a sensitivity of 96 % to diagnose a malignant lesion, a specificity of 88.4 %, an accuracy of 95.78 %, a positive predictive value of 98.70 %, and a negative predictive value of 73.33 %. Conclusions: The results of the present study therefore concluded that CT is a useful modality for the diagnosis of malignant liver masses.Ultrasound had high sensitivity, specificity for the hepatic masses. females were more effected than males. Among hepatic masses, HCC is the commonest. more...

Discovering what other people think has always been a key aspect of our information-gathering strategy. People can now actively utilize information technology to seek out and comprehend the ideas of others, thanks to the increased availability and popularity of opinion-rich resources such as online review sites and personal blogs. Because of its crucial function in understanding people's opinions, sentiment analysis (SA) is a crucial task. Existing research, on the other hand, is primarily focused on the English language, with just a small amount of study devoted to low-resource languages. For sentiment analysis, this work presented a new multi-class Urdu dataset based on user evaluations. The tweeter website was used to get Urdu dataset. Our proposed dataset includes 10,000 reviews that have been carefully classified into two categories by human experts: positive, negative. The primary purpose of this research is to construct a manually annotated dataset for Urdu sentiment analysis and to establish the baseline result. Five different lexicon- and rule-based algorithms including Naivebayes, Stanza, Textblob, Vader, and Flair are employed and the experimental results show that Flair with an accuracy of 70% outperforms other tested algorithms., Comment: Sentiment Analysis, Opinion Mining, Urdu language, polarity assessment, lexicon-based method more...

This study investigates the partial combustion technique for tar conversion using a modified experimental set up comprising a packed bed reactor with bed-inside probe for air supply. Simulated producer gas (SPG) and benzene were selected as a real producer gas alternative and model tar component respectively. The benzene conversion was investigated under different experimental conditions such as reactor temperature (650–900 °C), packed bed height (0–12 cm), residence time (1.2–1.9 s), air fuel ratio (0.2 and 0.3) and SPG composition. The results showed insignificant effect of temperature over benzene conversion while air fuel ratio of 0.3 caused high benzene conversion than at 0.2. Absence of packed bed lead high benzene conversion of 90% to polyaromatic hydrocarbons (PAHs) compared to similar low PAHs free benzene conversion of 32% achieved at both packed heights. In SPG composition effect, H2 and CH4 had a substantial inverse effect on benzene conversion. An increase in H2 concentration from 12 to 24 vol% increased the benzene conversion from 26 to 45% while an increase in CH4 concentration from 7 to 14 vol% reduced the benzene conversion from 28 to 4%. However, other SPG components had insignificant impacts on benzene conversion., Char and tar conversion in an internally heated packed bed more...

Innovation works as an engine of growth for the country and the backbone for the performance of the firm. Pakistan is a developing country and it is lagging behind in terms of innovation activities in the region. In Pakistan, due to the weaker quality of institutions, court fairness is biased. The objective of the study was to measure the effect of court fairness on the innovation of the firm in the case of Pakistan using the World Enterprise Survey. The results of the study indicate that court fairness increases the likelihood of innovation. From the perspective of the policy proposal, it is suggested that proper reforms in the judicial system must be initiated and it is the utmost need of the society, firms, and the nation as a whole. more...

Innovation works as an engine of growth for the country and the backbone for the performance of the firm. Pakistan is a developing country and it is lagging behind in terms of innovation activities in the region. In Pakistan, due to the weaker quality of institutions, court fairness is biased. The objective of the study was to measure the effect of court fairness on the innovation of the firm in the case of Pakistan using the World Enterprise Survey. The results of the study indicate that court fairness increases the likelihood of innovation. From the perspective of the policy proposal, it is suggested that proper reforms in the judicial system must be initiated and it is the utmost need of the society, firms, and the nation as a whole. more...

Innovation works as an engine of growth for the country and the backbone for the performance of the firm. Pakistan is a developing country and it is lagging behind in terms of innovation activities in the region. In Pakistan, due to the weaker quality of institutions, court fairness is biased. The objective of the study was to measure the effect of court fairness on the innovation of the firm in the case of Pakistan using the World Enterprise Survey. The results of the study indicate that court fairness increases the likelihood of innovation. From the perspective of the policy proposal, it is suggested that proper reforms in the judicial system must be initiated and it is the utmost need of the society, firms, and the nation as a whole. more...

Red wattled lapwing is commonly found and endemic species of Asian agricultural lands. Its preferred habitat is airy lands, rural and even urban areas. The main aims of current investigatory effort were the observation of different parameters of breeding ecology of Vanellus indicus including breeding sites, incubation period, the clutch size, survival rate of chicks and possible reasons of their mortality which are localized in Narowal district. Red wattled lapwings forage on several types of insects, snails, seeds, and of invertebrates. Experimental observations highlight that the annual breeding season is of average 26-30 days of V. Indicus begins from the March and till the end of August. Moreover, the weight of their eggs falls between 22.0 to 28.0g. These findings about local species may serve for next experimental designs based of on V. indicus and further focus should be on those factors which may improve its breeding. Similarly, the estimation of feeding preferences of this species can directly help in low cost biological control management for crops. more...

Red wattled lapwing is commonly found and endemic species of Asian agricultural lands. Its preferred habitat is airy lands, rural and even urban areas. The main aims of current investigatory effort were the observation of different parameters of breeding ecology of Vanellus indicus including breeding sites, incubation period, the clutch size, survival rate of chicks and possible reasons of their mortality which are localized in Narowal district. Red wattled lapwings forage on several types of insects, snails, seeds, and of invertebrates. Experimental observations highlight that the annual breeding season is of average 26-30 days of V. Indicus begins from the March and till the end of August. Moreover, the weight of their eggs falls between 22.0 to 28.0g. These findings about local species may serve for next experimental designs based of on V. indicus and further focus should be on those factors which may improve its breeding. Similarly, the estimation of feeding preferences of this species can directly help in low cost biological control management for crops. more...

Red wattled lapwing is commonly found and endemic species of Asian agricultural lands. Its preferred habitat is airy lands, rural and even urban areas. The main aims of current investigatory effort were the observation of different parameters of breeding ecology of Vanellus indicus including breeding sites, incubation period, the clutch size, survival rate of chicks and possible reasons of their mortality which are localized in Narowal district. Red wattled lapwings forage on several types of insects, snails, seeds, and of invertebrates. Experimental observations highlight that the annual breeding season is of average 26-30 days of V. Indicus begins from the March and till the end of August. Moreover, the weight of their eggs falls between 22.0 to 28.0g. These findings about local species may serve for next experimental designs based of on V. indicus and further focus should be on those factors which may improve its breeding. Similarly, the estimation of feeding preferences of this species can directly help in low cost biological control management for crops. more...

The prediction of the particle-size distribution (PSD) of the particulate systems in chemical engineering is very important in a variety of different contexts, such as parameter identification, troubleshooting, process control, design, product quality, production economics etc. The time evolution of the PSD can be evaluated by means of the population balance equation (PBE), which is a complex integro-differential equation, whose solution in practical cases always requires sophisticated numerical methods that may be computationally tedious. In this work, we propose a novel technique that tackles this issue by using an analytical time-stepping procedure (ATS) to resolve the PSD time dependency. The ATS is an explicit time integrator, taking advantage of the linear or almost linear time dependency of the discretized population balance equation. Thus, linear approximation of the source term is a precondition for the ATS simulations. The presented technique is compared with a standard variable step time integrator (MATLAB ODE15s stiff solver), for practical examples e.g. emulsion, aging cellulose process, cooling crystallization, reactive dissolution, and liquid-liquid extraction. The results show that this advancing in time procedure is accurate for all tested practical examples, allowing reproducing the same results given by standard time integrators in a fraction of the computational time. more...

Event Tree (ET) analysis is a widely used forward deductive safety analysis technique for decision-making at a system design stage. Existing ET tools usually provide Graphical Users Interfaces (GUI) for users to manually draw system-level ET diagrams, which consist of nodes and branches, describing all possible success and failure scenarios. However, these tools do not include some important ET analysis steps, e.g., the automatic generation and reduction of a complete system ET diagram. In this paper, we present a new Event Trees Modeling and Analysis (ETMA) tool to facilitate users to conduct a complete ET analysis of a given system. Some key features of ETMA include: (i) automatic construction of a complete ET model of real-world systems; (ii) deletion/reduction of unnecessary ET nodes and branches; (iii) partitioning of ET paths; and (iv) probabilistic analysis of the occurrence of a certain event. For illustration purposes, we utilize our ETMA tool to conduct the ET analysis of a protective fault trip circuit in power grid transmission lines. We also compared the ETMA results with Isograph, which is a well-known commercial tool for ET analysis., Comment: 21 pages, 10 figures, 4 tables, The 14th Annual IEEE International Systems Conference (SYSCON 2020) more...

Event Tree (ET) analysis is widely used as a forward deductive safety analysis technique for decision-making at the critical-system design stage. ET is a schematic diagram representing all possible operating states and external events in a system so that one of these possible scenarios can occur. In this report, we propose to use the HOL4 theorem prover for the formal modeling and step-analysis of ET diagrams. To this end, we developed a formalization of ETs in higher-order logic, which is based on a generic list datatype that can: (i) construct an arbitrary level of ET diagrams; (ii) reduce the irrelevant ET branches; (iii) partition ET paths; and (iv) perform the probabilistic analysis based on the occurrence of certain events. For illustration purposes, we conduct the formal ET stepwise analysis of an electrical power grid and also determine its System Average Interruption Frequency Index (SAIFI), which is an important indicator for system reliability., Comment: 17 pages, 3 figures more...

This study presents a novel method to recognize human physical activities using CNN followed by LSTM. Achieving high accuracy by traditional machine learning algorithms, (such as SVM, KNN and random forest method) is a challenging task because the data acquired from the wearable sensors like accelerometer and gyroscope is a time-series data. So, to achieve high accuracy, we propose a multi-head CNN model comprising of three CNNs to extract features for the data acquired from different sensors and all three CNNs are then merged, which are followed by an LSTM layer and a dense layer. The configuration of all three CNNs is kept the same so that the same number of features are obtained for every input to CNN. By using the proposed method, we achieve state-of-the-art accuracy, which is comparable to traditional machine learning algorithms and other deep neural network algorithms., Comment: IEEE ICET 2019 more...

Red wattled lapwing is commonly found and endemic species of Asian agricultural lands. Its preferred habitat is airy lands, rural and even urban areas. The main aims of current investigatory effort were the observation of different parameters of breeding ecology of Vanellus indicus including breeding sites, incubation period, the clutch size, survival rate of chicks and possible reasons of their mortality which are localized in Narowal district. Red wattled lapwings forage on several types of insects, snails, seeds, and of invertebrates. Experimental observations highlight that the annual breeding season is of average 26-30 days of V. Indicus begins from the March and till the end of August. Moreover, the weight of their eggs falls between 22.0 to 28.0g. These findings about local species may serve for next experimental designs based of on V. indicus and further focus should be on those factors which may improve its breeding. Similarly, the estimation of feeding preferences of this species can directly help in low cost biological control management for crops. more...

Red wattled lapwing is commonly found and endemic species of Asian agricultural lands. Its preferred habitat is airy lands, rural and even urban areas. The main aims of current investigatory effort were the observation of different parameters of breeding ecology of Vanellus indicus including breeding sites, incubation period, the clutch size, survival rate of chicks and possible reasons of their mortality which are localized in Narowal district. Red wattled lapwings forage on several types of insects, snails, seeds, and of invertebrates. Experimental observations highlight that the annual breeding season is of average 26-30 days of V. Indicus begins from the March and till the end of August. Moreover, the weight of their eggs falls between 22.0 to 28.0g. These findings about local species may serve for next experimental designs based of on V. indicus and further focus should be on those factors which may improve its breeding. Similarly, the estimation of feeding preferences of this species can directly help in low cost biological control management for crops. more...

This work presents the experimentally determined density (rho), viscosity (eta), speed of sound (u), and surface tension (sigma) data for tert-amyl methyl ether (TAME) + n-hexane and TAME + m-xylene systems at several temperatures (298.15, 308.15, 318.15, 323.15, and 328.15 K). These experimentally determined thermophysical data are utilized to compute various excess/deviation parameters such as molar volume (V-E), isentropic compressibility (K-s(E)), speed of sound (u(E)), deviation in viscosity (Delta In eta), isobaric thermal expansion coefficient (alpha(E)(P)), and surface tension (sigma(E)). The inspection of parameters response may interpret the existing specific molecular interactions as well as the mixing behavior of solutions. The critical analysis of observed parametric behavior have unveiled the strong and weak molecular interactions in TAME with m-xylene and TAME with n-hexane systems, respectively. more...

Dynamic Fault Trees (DFTs) is a widely used failure modeling technique that allows capturing the dynamic failure characteristics of systems in a very effective manner. Simulation and model checking have been traditionally used for the probabilistic analysis of DFTs. Simulation is usually based on sampling and thus its results are not guaranteed to be complete, whereas model checking employs computer arithmetic and numerical algorithms to compute the exact values of probabilities, which contain many round-off errors. Leveraging upon the expressive and sound nature of higher-order-logic (HOL) theorem proving, we propose, in this work, a formalization of DFT gates and their probabilistic behavior as well as some of their simplification properties in HOL. This formalization would allow us to conduct the probabilistic analysis of DFTs by verifying generic mathematical expressions about their behavior in HOL. In particular, we formalize the AND, OR, Priority-AND, Functional DEPendency, Hot SPare, Cold SPare and the Warm SPare gates and also verify their corresponding probabilistic expressions in HOL. Moreover, we formally verify an important property, Pr(X more...

In recent years, the decoding algorithms in communication networks are becoming increasingly complex aiming to achieve high reliability in correctly decoding received messages. These decoding algorithms involve computationally complex operations requiring high performance computing hardware, which are generally expensive. A cost-effective solution is to enhance the Instruction Set Architecture (ISA) of the processors by creating new custom instructions for the computational parts of the decoding algorithms. In this paper, we propose to utilize the custom instruction approach to efficiently implement the widely used Viterbi decoding algorithm by adding the assembly language instructions to the ISA of DLX, PicoJava II and NIOS II processors, which represent RISC, stack and FPGA-based soft-core processor architectures, respectively. By using the custom instruction approach, the execution time of the Viterbi algorithm is significantly improved by approximately 3 times for DLX and PicoJava II, and by 2 times for NIOS II., Comment: 7 Pages, 4 Figures, 2018 14th IEEE/ASME International Conference on Mechatronic and Embedded Systems and Applications (MESA) more...

World demand for textiles is on the rise and there is a need for fiber source that does not require arable land. Ioncell-F is a novel method of producing fiber from pulp. It uses ionic liquid [DBNH][OAc] to dissolve cellulose. Ionic liquid is expensive so it has to be recycled to make the process economical. Ionic liquid is thermally unstable, therefore the recycling has to be done with moderate temperatures. One way to separate and recycle ionic liquid from water is thin film evaporation. The purpose of this study was to model the evaporation of water from water/[DBNH][OAc] mixture in an agitated thin film evaporator in flowsheet simulator Aspen Plus. Accurate modeling of the evaporator is needed to design and optimize the recycling process. The study also studied the applicability of multiple-effect evaporation. Various modeling approaches were studied to simulate the thin film evaporator and an Aspen Plus model was developed based on batch distillation theory. The performance of the model was compared to an earlier developed model based on flash drum model and experimental data. The batch model gave more accurate results than the often used flash model. The model did not include the hydrolysis product of the ionic liquid, implementation of which should be the focus in future works. A case study was conducted and the applicability of double-effect evaporation was tested with the model. A rapid boiling point elevation at low water concentrations made it harder to implement multiple-effect evaporation in recycling of the ionic liquid. It could be done with right pressure and temperature settings for most of the evaporation, with one additional evaporator to achieve desired water content. Multiple-effect evaporation proved useful in both achieving purer vapor and lowering the total required heating power., Maailmanlaajuinen tekstiilin kysyntä on kasvussa, ja tekstiilin lähteeksi tarvitaan raaka-aineita, jotka eivät vie tilaa viljeltävältä maalta. Ioncell-F on uusi prosessi, joka voi tuottaa kuitua sellusta. Se käyttää ionista nestettä [DBNH][OAc] liuottaakseen selluloosan. Ioninen neste on kallista, joten se täytyy erottaa vedestä ja kierrättää, jotta prosessi on kannattava. Se kuitenkin myös hajoaa korkeissa lämpötiloissa, joten erotus täytyy tehdä matalissa lämpötiloissa. Yksi keino tähän on ohutfilmihaihdutin. Tämän työn tarkoituksena oli mallintaa veden haihdutusta veden ja ionisen nesteen seoksesta ohutfilmihaihduttimessa Aspen-Plus ohjelmalla. Haihduttimen tarkka mallinnus on tärkeää kierrätysprosessin suunnittelemiseksi ja optimoinniksi. Työssä myös selvitettiin, olisiko monivaihelauhdutus mahdollista. Erilaisia malllinnusvaihtoehtoja käsiteltiin ja panostislaukseen pohjautuva malli valittiin keskittymispohjaksi. Aspen Plus malli kehitettiin panostislausteorian pohjalta, ja sen tuloksia verrattiin aiemmin kehitettyyn flash-malliin sekä kokeellisiin tuloksiin. Panostislausmallin tulokset olivat lähempänä kokeellisia, kuin flash-malli. Kummastakin mallista kuitenkin puuttuu ionisen nesteen hydrolyysituote, mikä tuo epätarkkuutta mallinnukseen. Sen sisältäminen mallinnukseen tulisi olla seuraavien tutkimusten kohde. Panostislausmallille tehtiin tapaustutkimus ja monivaihelauhdutuksen sisällyttämisen mahdollisuutta haihdutusprosessiin arvioitiin. Kiehumispisteen kohoama vähäisissä vesipitoisuuksissa on nopeaa, mikä vaikeuttaa monivaihelauhdutuksen käyttämistä. Oikeilla paineilla ja lämpötiloilla se saatiin kuitenkin sisällytettyä, jos viimeisen haihduttimen lämmittämiseen käytettiin ulkoista energiaa. Monivaihelauhdutus säästi selvästi lämmitysenergiaa sekä auttoi kierrätystä jakamalla höyryn suureen virtaan erittäin puhdasta vesihöyryä ja pienempään virtaan, jossa lähes kaikki höyrystynyt ioninen neste oli. more...

Use of zinc (Zn) fertilisers may be cost-effective in increasing crop yields and in alleviating dietary Zn deficiency. However, Zn fertilisers are underutilised in many countries despite the widespread occurrence of Zn-deficient soils. Here, increased Zn fertiliser-use scenarios were simulated for wheat production in Punjab and Sindh Provinces, Pakistan. Inputs and outputs were valued in terms of both potential yield gains as well as health gains in the population. Methods The current dietary Zn deficiency risk of 23.9 % in Pakistan was based on food supply and wheat grain surveys. “Disability-adjusted life years (DALYs) lost” are a common metric of disease burden; an estimated 245,000 DALYs y−1 are lost in Punjab and Sindh due to Zn deficiency. Baseline Zn fertiliser-use of 7.3 kt y−1 ZnSO4.H2O was obtained from published and industry sources. The wheat area currently receiving Zn fertilisers, and grain yield responses of 8 and 14 % in Punjab and Sindh, respectively, were based on a recent survey of >2500 farmers. Increased grain Zn concentrations under Zn fertilisation were estimated from literature data and converted to improved Zn intake in humans and ultimately a reduction in DALYs lost. more...

Use of zinc (Zn) fertilisers may be cost-effective in increasing crop yields and in alleviating dietary Zn deficiency. However, Zn fertilisers are underutilised in many countries despite the widespread occurrence of Zn-deficient soils. Here, increased Zn fertiliser-use scenarios were simulated for wheat production in Punjab and Sindh Provinces, Pakistan. Inputs and outputs were valued in terms of both potential yield gains as well as health gains in the population. Methods The current dietary Zn deficiency risk of 23.9 % in Pakistan was based on food supply and wheat grain surveys. “Disability-adjusted life years (DALYs) lost” are a common metric of disease burden; an estimated 245,000 DALYs y−1 are lost in Punjab and Sindh due to Zn deficiency. Baseline Zn fertiliser-use of 7.3 kt y−1 ZnSO4.H2O was obtained from published and industry sources. The wheat area currently receiving Zn fertilisers, and grain yield responses of 8 and 14 % in Punjab and Sindh, respectively, were based on a recent survey of >2500 farmers. Increased grain Zn concentrations under Zn fertilisation were estimated from literature data and converted to improved Zn intake in humans and ultimately a reduction in DALYs lost. more...

The study aims to find the influence of the job stress on the doctor’s performance in the public hospitals of Peshawar city. No doubt the profession of doctors is very respectable and they are doing a good work serving the people of society but their work environment must have some sort of influence on their performance as well. That’s why this study was taken in to consideration to study the doctors’ performance in the public hospitals. This study was designed to assess the doctor’s performance in public hospitals only. Sample size was drawn on the basis of simple random sampling technique as the data was of quantitative in nature. Data was collected through a questionnaire which was developed by the research himself and to find the reliability and validity a pilot test was done with the data collection tool which showed some mistakes and those mistakes were rectified. Due to limited time period and resources of the researcher, the researcher has drawn 150 sample size of the total population of the doctors in the public hospitals of Peshawar city. A total of 150samples (50 from each public hospitals respectively of Peshawar) data were collected .Out of 150 study participants; it was observed that doctors in KTH, LRH and HMC were suffering from job stress collectively. Their performance was affected and the result of this study highlight the significant result in which it was concluded that job stress had a negative impact on the doctor’s performance in the public hospitals of Peshawar. more...

The study aims to find the influence of the job stress on the doctor’s performance in the public hospitals of Peshawar city. No doubt the profession of doctors is very respectable and they are doing a good work serving the people of society but their work environment must have some sort of influence on their performance as well. That’s why this study was taken in to consideration to study the doctors’ performance in the public hospitals. This study was designed to assess the doctor’s performance in public hospitals only. Sample size was drawn on the basis of simple random sampling technique as the data was of quantitative in nature. Data was collected through a questionnaire which was developed by the research himself and to find the reliability and validity a pilot test was done with the data collection tool which showed some mistakes and those mistakes were rectified. Due to limited time period and resources of the researcher, the researcher has drawn 150 sample size of the total population of the doctors in the public hospitals of Peshawar city. A total of 150samples (50 from each public hospitals respectively of Peshawar) data were collected .Out of 150 study participants; it was observed that doctors in KTH, LRH and HMC were suffering from job stress collectively. Their performance was affected and the result of this study highlight the significant result in which it was concluded that job stress had a negative impact on the doctor’s performance in the public hospitals of Peshawar. more...

Dynamic fault trees (DFTs) have emerged as an important tool for capturing the dynamic behavior of system failure. These DFTs are then analyzed qualitatively and quantitatively using stochastic or algebraic methods to judge the failure characteristics of the given system in terms of the failures of its sub-components. Model checking has been recently proposed to conduct the failure analysis of systems using DFTs with the motivation to provide a rigorous failure analysis of safety-critical systems. However, model checking has not been used for the DFT qualitative analysis and the reduction algorithms used in model checking are usually not formally verified. Moreover, the analysis time grows exponentially with the increase of the number of states. These issues limit the usefulness of model checking for analyzing complex systems used in safety-critical domains, where the accuracy and completeness of analysis matters the most. To overcome these limitations, we propose a comprehensive methodology to perform the qualitative and quantitative analysis of DFTs using an integration of theorem proving and model checking based approaches. For this purpose, we formalized all the basic dynamic fault tree gates using higher-order logic based on the algebraic approach and formally verified some of the simplification properties. This formalization allows us to formally verify the equivalence between the original and reduced DFTs using a theorem prover, and conduct the qualitative analysis. We then use model checking to perform the quantitative analysis of the formally verified reduced DFT. We applied our methodology to five benchmarks and the results show that the formally verified reduced DFT was analyzed using model checking with up to six times less states and up to 133000 times faster. more...

In this paper we present a software tool for melanoma border detection (MBD). It has been designed to be incorporated in any Computer Aided Diagnosis Tool (CAD) for early detection of melanoma in mass screening programs. The tool is completely automatic, posses a user-friendly interface and does not require any specific hardware. The main steps followed by the implemented algorithm are: uneven illumination correction, color contrast improvement and color image segmentation. All of them are performed in the uniform color space CIE L * a * b * in order to achieve a complete adaptation to human color perception. The program is able to provide not only the final obtained segmentation result but also intermediate graphical outcomes, guiding the user in the process of melanoma detection. This simple, friendly but powerful interface can serve as a support for the medical personnel in the melanoma diagnostic process. The MBD software and some samples of the dermoscopy images used can be downloaded at http://cs.ntu. edu.pk/research.php. more...

In this paper we present a software tool for melanoma border detection (MBD). It has been designed to be incorporated in any Computer Aided Diagnosis Tool (CAD) for early detection of melanoma in mass screening programs. The tool is completely automatic, posses a user-friendly interface and does not require any specific hardware. The main steps followed by the implemented algorithm are: uneven illumination correction, color contrast improvement and color image segmentation. All of them are performed in the uniform color space CIE L * a * b * in order to achieve a complete adaptation to human color perception. The program is able to provide not only the final obtained segmentation result but also intermediate graphical outcomes, guiding the user in the process of melanoma detection. This simple, friendly but powerful interface can serve as a support for the medical personnel in the melanoma diagnostic process. The MBD software and some samples of the dermoscopy images used can be downloaded at http://cs.ntu. edu.pk/research.php. more...

In this paper we present a software tool for melanoma border detection (MBD). It has been designed to be incorporated in any Computer Aided Diagnosis Tool (CAD) for early detection of melanoma in mass screening programs. The tool is completely automatic, posses a user-friendly interface and does not require any specific hardware. The main steps followed by the implemented algorithm are: uneven illumination correction, color contrast improvement and color image segmentation. All of them are performed in the uniform color space CIE L * a * b * in order to achieve a complete adaptation to human color perception. The program is able to provide not only the final obtained segmentation result but also intermediate graphical outcomes, guiding the user in the process of melanoma detection. This simple, friendly but powerful interface can serve as a support for the medical personnel in the melanoma diagnostic process. The MBD software and some samples of the dermoscopy images used can be downloaded at http://cs.ntu. edu.pk/research.php. more...

In this paper we present a software tool for melanoma border detection (MBD). It has been designed to be incorporated in any Computer Aided Diagnosis Tool (CAD) for early detection of melanoma in mass screening programs. The tool is completely automatic, posses a user-friendly interface and does not require any specific hardware. The main steps followed by the implemented algorithm are: uneven illumination correction, color contrast improvement and color image segmentation. All of them are performed in the uniform color space CIE L * a * b * in order to achieve a complete adaptation to human color perception. The program is able to provide not only the final obtained segmentation result but also intermediate graphical outcomes, guiding the user in the process of melanoma detection. This simple, friendly but powerful interface can serve as a support for the medical personnel in the melanoma diagnostic process. The MBD software and some samples of the dermoscopy images used can be downloaded at http://cs.ntu. edu.pk/research.php. more...

In this paper we present a software tool for melanoma border detection (MBD). It has been designed to be incorporated in any Computer Aided Diagnosis Tool (CAD) for early detection of melanoma in mass screening programs. The tool is completely automatic, posses a user-friendly interface and does not require any specific hardware. The main steps followed by the implemented algorithm are: uneven illumination correction, color contrast improvement and color image segmentation. All of them are performed in the uniform color space CIE L * a * b * in order to achieve a complete adaptation to human color perception. The program is able to provide not only the final obtained segmentation result but also intermediate graphical outcomes, guiding the user in the process of melanoma detection. This simple, friendly but powerful interface can serve as a support for the medical personnel in the melanoma diagnostic process. The MBD software and some samples of the dermoscopy images used can be downloaded at http://cs.ntu. edu.pk/research.php. more...

Reducing the interconnect size with each technology node and increasing speed with each generation increases IR-drop and Ldi/dt noise. In addition to this, the drive for more integration increases the average current requirement for modern ULSI design. Simultaneous switching of core logic blocks and I/O drivers produces large current transients due to power distribution network parasitics at high clock frequency. The current transients are injected into the power distribution planes thereby inducing noise in the supply voltage. The part of the noise that is caused by switching of the internal logic load is core switching noise. The core logic switches at much higher speed than driver speed whereas the package inductance is less than the on-chip inductance in modern BGA packages. The core switching noise is currently gaining more attention for three-dimensional integrated circuits where on-chip inductance is much higher than the board and package inductance due to smaller board, and package. The switching noise of the driver is smaller than the core switching noise due to small driver size and reduced capacitance associated with short on-board wires for three-dimensional integrated circuits. The load increases with the addition of each die. The power distribution TSV pairs to supply each extra die also introduce additional parasitic. The core switching noise may propagate through substrate and consequently through interconnecting TSVs to different dies in heterogeneous integrated system. Core switching noise may lead to decreased device drive capability, increased gate delays, logic errors, and reduced noise margins. The actual behavior of the on-chip load is not well known in the beginning of the design cycle whereas altering the design during later stages is not cost effective. The size of a three-dimensional power distribution network may reach billions of nodes with the addition of dies in a vertical stack. The traditional tools may run out of time and memory dur, QC 20121015 more...

The 3D-DRAM stacked over the processor is a vibrant technique in order to overcome the memory wall as well as the bandwidth wall problems. We considered a system with two DRAM dies over a single processor die. We assumed the decoupling capacitors to be placed on each DRAM die and connected to the power distribution TSV pairs, where the TSVs pass through the DRAM stack. In this paper we proposed a mathematical model for the optimum value of the decoupling capacitance on each DRAM die along with the optimum values of the effective resistance of the interconnecting power distribution TSV pairs in order to ensure the power integrity of the logic load during switching. The proposed model has a maximum of 1.1% error as compared to the Ansoft Nexxim4.1., QC 20121015 more...

In this article we propose an efficient and accurate model to estimate peak-to-peak core switching noise, caused by simultaneous switching of logic loads along a vertical chain of power distribution TSV pairs in a 3D stack of dies interconnected through TSVs. The proposed model is accurate with only a 2–3% difference in peak-to-peak core switching noise as compared to the Ansoft Nexxim4.1 equivalent model. The proposed model is 3–4 times faster than Ansoft Nexxim4.1 and uses two times less memory as compared to the Ansoft Nexxim4.1 equivalent model. In this article we also thoroughly establish design guidelines for almost flat output impedance magnitude at each stage of a vertical chain of power distribution TSV pairs to realize a resonance free scenario over a wide operating frequency range. We also establish decoupling capacitance design guidelines based on the optimum output impedance and critically damped supply voltage for the core logic for each stage of a vertical chain of power distribution TSV pairs., QC 20121015 more...

QC 20121015

Reducing the interconnect size with each technology node and increasing speed with each generation increases IR-drop and Ldi/dt noise. In addition to this, the drive for more integration increases the average current requirement for modern ULSI design. Simultaneous switching of core logic blocks and I/O drivers produces large current transients due to power distribution network parasitics at high clock frequency. The current transients are injected into the power distribution planes thereby inducing noise in the supply voltage. The part of the noise that is caused by switching of the internal logic load is core switching noise. The core logic switches at much higher speed than driver speed whereas the package inductance is less than the on-chip inductance in modern BGA packages. The core switching noise is currently gaining more attention for three-dimensional integrated circuits where on-chip inductance is much higher than the board and package inductance due to smaller board, and package. The switching noise of the driver is smaller than the core switching noise due to small driver size and reduced capacitance associated with short on-board wires for three-dimensional integrated circuits. The load increases with the addition of each die. The power distribution TSV pairs to supply each extra die also introduce additional parasitic. The core switching noise may propagate through substrate and consequently through interconnecting TSVs to different dies in heterogeneous integrated system. Core switching noise may lead to decreased device drive capability, increased gate delays, logic errors, and reduced noise margins. The actual behavior of the on-chip load is not well known in the beginning of the design cycle whereas altering the design during later stages is not cost effective. The size of a three-dimensional power distribution network may reach billions of nodes with the addition of dies in a vertical stack. The traditional tools may run out of time and memory dur, QC 20121015 more...

Reducing the interconnect size with each technology node and increasing speed with each generation increases IR-drop and Ldi/dt noise. In addition to this, the drive for more integration increases the average current requirement for modern ULSI design. Simultaneous switching of core logic blocks and I/O drivers produces large current transients due to power distribution network parasitics at high clock frequency. The current transients are injected into the power distribution planes thereby inducing noise in the supply voltage. The part of the noise that is caused by switching of the internal logic load is core switching noise. The core logic switches at much higher speed than driver speed whereas the package inductance is less than the on-chip inductance in modern BGA packages. The core switching noise is currently gaining more attention for three-dimensional integrated circuits where on-chip inductance is much higher than the board and package inductance due to smaller board, and package. The switching noise of the driver is smaller than the core switching noise due to small driver size and reduced capacitance associated with short on-board wires for three-dimensional integrated circuits. The load increases with the addition of each die. The power distribution TSV pairs to supply each extra die also introduce additional parasitic. The core switching noise may propagate through substrate and consequently through interconnecting TSVs to different dies in heterogeneous integrated system. Core switching noise may lead to decreased device drive capability, increased gate delays, logic errors, and reduced noise margins. The actual behavior of the on-chip load is not well known in the beginning of the design cycle whereas altering the design during later stages is not cost effective. The size of a three-dimensional power distribution network may reach billions of nodes with the addition of dies in a vertical stack. The traditional tools may run out of time and memory dur, QC 20121015 more...

Reducing the interconnect size with each technology node and increasing speed with each generation increases IR-drop and Ldi/dt noise. In addition to this, the drive for more integration increases the average current requirement for modern ULSI design. Simultaneous switching of core logic blocks and I/O drivers produces large current transients due to power distribution network parasitics at high clock frequency. The current transients are injected into the power distribution planes thereby inducing noise in the supply voltage. The part of the noise that is caused by switching of the internal logic load is core switching noise. The core logic switches at much higher speed than driver speed whereas the package inductance is less than the on-chip inductance in modern BGA packages. The core switching noise is currently gaining more attention for three-dimensional integrated circuits where on-chip inductance is much higher than the board and package inductance due to smaller board, and package. The switching noise of the driver is smaller than the core switching noise due to small driver size and reduced capacitance associated with short on-board wires for three-dimensional integrated circuits. The load increases with the addition of each die. The power distribution TSV pairs to supply each extra die also introduce additional parasitic. The core switching noise may propagate through substrate and consequently through interconnecting TSVs to different dies in heterogeneous integrated system. Core switching noise may lead to decreased device drive capability, increased gate delays, logic errors, and reduced noise margins. The actual behavior of the on-chip load is not well known in the beginning of the design cycle whereas altering the design during later stages is not cost effective. The size of a three-dimensional power distribution network may reach billions of nodes with the addition of dies in a vertical stack. The traditional tools may run out of time and memory dur, QC 20121015 more...