Sigma Levels Research Articles

Using Kano's model to incorporate Six Sigma analysis in customer satisfaction measurement

The Six Sigma approach is a statistical concept that analyses a process in terms of defects and has been well recognised as an important tool for continuous improvement. Since sigma level can be used as a measure of the number of dissatisfied customers (defects), it can be assumed that there is a direct relationship between satisfaction ratings and sigma levels. However, higher sigma levels for certain attributes do not necessarily translate to correspondingly higher customer satisfaction scores, while some attributes with higher satisfaction scores may not have a very high sigma level. The main goal of this paper is to incorporate the concept of Six Sigma analysis in customer satisfaction measurement by introducing the principles of Kano's customer satisfaction model in order to derive important information for the selection of strategic actions. The proposed approach has been implemented for the evaluation of customer satisfaction from Greek mobile service providers.

Analysis of basic status and 15 quality indicators in clinical laboratory of medical institutions in Qinghai province

Objective To investigate the basic status and the 15 quality indicators in clinical laboratory of medical institutionin in Qinghai provinces, and to understand the quality status. Methods Clinet-EQA system was applied by Qinghai Center for Clinical Laboratories to provide the electronic questionnaire for the clinical laboratory of 106 medical institutions in April 2016 and report related results online. The software of Clinet-EQA system and SPSS13.0 were used for 15 quality indicators for statiatical analysis, 13 indicators expressed in rate were further evaluated with sigma scales. Results Totally 102 laboratories returned questionnaires, the rate was of 96.2%. 8/13 quality indicators of the overall sigma levels were all >3. The average level of 4 quality indicators such as the sample type error rate was slightly lower than the national . Comparison of the 4 quality indicators of each grade hospital in Qinghai and the same grade hospital in the national, secondary hospital in clinical chemistry, immunology, clinical examination, microbiology in the four major performed better than tertiary hospital. In routine examination, pre-analytical TAT average level of clinical chemistry and immunology was about 50 min, and of blood, urine and stool was 45 min. Pre-analytical TAT in emergency examination for all four disciplines were about 15 min. Intra-analytical TAT for clinical chemistry was the longest, which was 120 min for routine examination and 40 min for emergency examination, respectiely. The average level of the median TAT of blood, urine and stool in routine examination of Intra-analytical in Qinghai was longer than the national.For example of clinical chemistry, routine examination both in pre-analytical TAT and in Intra-analytical TAT was statistically significant in different scales of laboratories, and emergency examination in pre-analytical TAT and in Intra-analytical TAT was not statistically significant. Conclusions 4/13 quality indicators which expressed in rate in the average level in Qinghai province were lower than the national, the average level of the median TAT of blood, urine and stool in routine examination of Intra-analytical in Qinghai was longer than the national.The laboratory should focus on the weak links and continue improvement . (Chin J Lab Med, 2017, 40: 885-889) Key words: Laboratory; Investigation; Quality indicators

Numerical modeling of storm surges in the coast of Mozambique: the cases of tropical cyclones Bonita (1996) and Lisette (1997)

The coast of Mozambique is often affected by storms, particularly tropical cyclones during summer or sometimes midlatitude systems in the southern part. Storm surges combined with high freshwater discharge can drive huge coastal floods, affecting both urban and rural areas. To improve the knowledge about the impact of storm surges in the coast of Mozambique, this study presents the first attempt to model this phenomenon through the implementation of the Princeton Ocean Model (POM) in the Southwestern Indian Ocean domain (SWIO; 2–32°S, 28–85°E) using a regular grid with 1/6° of spatial resolution and 36 sigma levels. The simulation was performed for the period 1979–2010, and the most interesting events of surges were related to tropical cyclones Bonita (1996) and Lisette (1997) that occurred in the Mozambique Channel. The results showed that the model represented well the amplitude and phase of principal lunar and solar tidal constituents, as well as it captured the spatial pattern and magnitudes of SST with slight positive bias in summer and negative bias in winter months. In terms of SSH, the model underestimated the presence of mesoscale eddies, mainly in the Mozambique Channel. Our results also showed that the atmospheric sea level pressure had a significant contribution to storm heights during the landfall of the tropical cyclones Bonita (1996) and Lisette (1997) in the coast of Mozambique contributing with about 20 and 16% of the total surge height for each case, respectively, surpassing the contribution of the tide-surge nonlinear interactions by a factor of 2.

Evaluation of clinical chemistry tests in emergency laboratory by sigma metrics

Abstract Aim Emergency department laboratories, besides from giving accurate results, should be quick enough in order not to delay patient care. Giving fast results doesn’t mean to ignore quality, rather it should always be improved to prevent erroneous results. Six sigma is a modern assessment of quality which is used to determine the analytical performance. Our aim was to evaluate the analytical performance of clinical chemistry tests in our emergency department laboratory by using sigma metrics. Materials and methods Our study was performed by using the internal and external quality assessment data of 13 clinical chemistry tests of emergency laboratory. Sigma levels were calculated using bias, coefficient of variation and total allowable error (TEa) ratios of CLIA, Ricos, Rilibak and Turkey. Results Sigma levels of various tests (CK, amylase, ALT, AST, urea, creatinine, total bilirubin, sodium and chloride) were found to be ≥6 according to different TEa’s, whereas the performance of sodium, potassium and chloride were unsatisfactory, according to TEa’s of CLIA, Ricos and Rilibak. Conclusion Since most of our sigma values were found to be over 3, the analytical performance of clinical chemistry tests was thought to be acceptable and our laboratory can be regarded as a qualified emergency laboratory.

The Evaluation of Analytical Performance of Immunoassay Tests by using Six-sigma Method.

SummaryBackgroundThe Six-Sigma Methodology is a quality measurement method in order to evaluate the performance of the laboratory. In the present study, it is aimed to evaluate the analytical performance of our laboratory by using the internal quality control data of immunoassay tests and by calculating process sigma values.MethodsBiological variation database (BVD) are used for Total Allowable Error (TEa). Sigma values were determined from coefficient of variation (CV) and bias resulting from Internal Quality Control (IQC) results for 3 subsequent months. If the sigma values are ≥6, between 3 and 6, and <3, they are classified as »world-class«, »good« or »un - acceptable«, respectively.ResultsA sigma value >6 was found for TPSA and TSH for the both levels of IQC for 3 months. When the sigma values were analyzed by calculating the mean of 3 months, folate, LH, PRL, TPSA, TSH and vitamin B12 were found >6. The mean sigma values of CA125, CA15-3, CA19-9, CEA, cortisol, ferritin, FSH, FT3, PTH and testosteron were >3 for 3-months. However, AFP, CA125 and FT4 produced sigma values <3 for varied months.ConclusionWhen the analytical performance was evaluated according to Six-Sigma levels, it was generally found as good. It is possible to determine the test with high error probability by evaluating the fine sigma levels and the tests that must be quarded by a stringent quality control regime. In clinical chemistry laboratories, an appropriate quality control scheduling should be done for each test by using Six-Sigma Methodology.

Measurement and Improvement the Quality of the Compressive Strength of Product Concrete

The research dealt with studying path technology to manufacture of concrete cubesaccording to specification design of Iraq to the degree of concrete C20 No. 52 of 1984, and inwhich sample was cubic shape and the dimensions (150 × 150 × 150) mm for each dimensionsand the proportion of mixing of the concrete is (1:2:4) using in the casting floor. For concreteresistance required that achieve the degree of confidence of 100%, were examinedcompressive strength 40 samples of concrete cubes of age 28 days in the Labs section of CivilDepartment – Technical Institute of Babylon, all made from the same mixing concrete. Where,these samples classified within the acceptable tests were adopted in the implementation ofinvestment projects in the construction sector. The research aims first, to measure thecompressive strength of concrete cubes because the decrease or increase the compressivestrength from specification design contributes to the failure of investment projects in theconstruction sector therefore, test was classified units that produced within damaged units.Second, to study an improvement the quality of compressive strength of concrete cubes.Results show that the proportion of damaged cubes are 0.00685, compressive strength wasachieve confidence level 99.5% and producing of concrete cubes within the acceptable level ofquality (3 Sigma). The quality of compressive strength was improved to good level useadvanced sigma levels.

Measurement and Improvement the Quality of the Compressive Strength of Product Concrete

The research dealt with studying path technology to manufacture of concrete cubes according to specification design of Iraq to the degree of concrete C20 No. 52 of 1984, and in which sample was cubic shape and the dimensions (150 × 150 × 150) mm for each dimensions and the proportion of mixing of the concrete is (1:2:4) using in the casting floor. For concrete resistance required that achieve the degree of confidence of 100%, were examined compressive strength 40 samples of concrete cubes of age 28 days in the Labs section of Civil Department – Technical Institute of Babylon, all made from the same mixing concrete. Where, these samples classified within the acceptable tests were adopted in the implementation of investment projects in the construction sector. The research aims first, to measure the compressive strength of concrete cubes because the decrease or increase the compressive strength from specification design contributes to the failure of investment projects in the construction sector therefore, test was classified units that produced within damaged units. Second, to study an improvement the quality of compressive strength of concrete cubes. Results show that the proportion of damaged cubes are 0.00685, compressive strength was achieve confidence level 99.5% and producing of concrete cubes within the acceptable level of quality (3 Sigma). The quality of compressive strength was improved to good level use advanced sigma levels . DOI: http://dx.doi.org/10.25130/tjes.24.2017.20

Numerical simulation on Bay of Bengal's response to cyclones using the Princeton ocean model

ABSTRACT This study used the Princeton ocean model (POM) which includes second-order turbulent closure scheme to investigate the fluid dynamics of the Bay of Bengal (BoB) in the upper ocean's response to a cyclone. The model uses an orthogonal curvilinear grid and 26 sigma levels in conformity with realistic bottom topography. The model is forced with wind and heat plus salinity fluxes as surface forcing to simulate the BoB's response during a cyclone. In order to provide the realistic cyclonic vortex the model as input, the synthetic cyclonic vortex is generated and superimposed on the QSCAT/NCEP blended ocean wind fields. Analyses of results show significant sea surface temperature (SST) cooling on both sides of the storm track. This cooling could be attributed to the strong cyclonic winds, surface divergence and upwelling. However, less commonly observed features such as a leftward bias in SST cooling due to the relatively slower motion of TC and southward moving coastal boundary currents are also reported in this study. Model SST is compared with the observed Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) filled up SST for the evaluation of the model's performance. Moreover, not only sea surface cooling but subsurface warming due to intense downwelling and coastal jet parallel to the coast were also observed in the model's simulation. The mixed layer depth (MLD) variation is revealed by the model. MLD deepening due to the convergence of near surface flow at the periphery of the cyclone is observed; however, beneath the cyclone centre, in the direction of the track the upsloping of isotherms due to the surface divergence and upwelling causes the shoaling of the MLD. Modeled surface currents are compared with 5-day interval OSCAR (Ocean Surface Current Analyses - Real time) surface currents, which are not very coherent, though some of the important features like higher values of boundary layer currents are captured. However, strong near surface, asymmetrical responses such as divergent currents in the open oceanic region are reflected by the model but when the cyclone approaches the coast the current patterns do not show the right bias due to interaction with the coast.

Six Sigma methodology for reducing defects in manufacturing industry - a case study

Owing to global competition in manufacturing sectors, customer demand for high quality product and for product variety is continuously increasing. Consequently, it has become necessary to enhance productivity and performance in order to make the process robust to quality. The present work deals with the application of DMAIC technique in manufacturing industry for quality improvement and reduction of muffler line defects. The DMAIC cycle has been applied to the critical product under study to ascertain the important benefits occurring for business improvement in the manufacturing industry of Northern India. The findings revealed significant enhancement in sigma level from 2.89 to 3.16 and process yield was increased from 91.73% to 95.19%. This study is an attempt to access the performance of Six Sigma approach through systematically implementation of DMAIC cycle. These enhanced sigma levels leads to high quality and fewer variations. The results showed that the rejection rate was reduced from 8.27% to 4.81% and saving in cost of Rs. 940,800/- has been achieved.

Six Sigma evaluation using process capability and &lt;i&gt;&lt;span style="text-decoration: overline"&gt;X&lt;/span&gt;&lt;/i&gt; control chart for reducing variance in oil density characteristic: a study in Yemen

This paper presents Six Sigma evaluation based on process capability with -X control chart to reduce variations in the oil density characteristics in an oil refinery process in Aden, Yemen. Twenty-five oil density samples with normal distribution were randomly collected, and each sample consisted of four items. Analysis indicated that the levels of sigma employed in Aden refinery are less than 3 σ. The results of this study suggested that the -X chart based on six sigma estimation method is significant to reduce variance in the oil density characteristic. In addition, the sigma levels increase when the process capability increases. Thus, the increment in sigma levels leads to improvements in the performance of the process refinery of oil density characteristic. Finally, this paper provides the necessary fundamentals and knowledge for quality control researchers and engineers to reduce variances by using Six Sigma.

Six Sigma methodology for reducing defects in manufacturing industry - a case study

Owing to global competition in manufacturing sectors, customer demand for high quality product and for product variety is continuously increasing. Consequently, it has become necessary to enhance productivity and performance in order to make the process robust to quality. The present work deals with the application of DMAIC technique in manufacturing industry for quality improvement and reduction of muffler line defects. The DMAIC cycle has been applied to the critical product under study to ascertain the important benefits occurring for business improvement in the manufacturing industry of Northern India. The findings revealed significant enhancement in sigma level from 2.89 to 3.16 and process yield was increased from 91.73% to 95.19%. This study is an attempt to access the performance of Six Sigma approach through systematically implementation of DMAIC cycle. These enhanced sigma levels leads to high quality and fewer variations. The results showed that the rejection rate was reduced from 8.27% to 4.81% and saving in cost of Rs. 940,800/- has been achieved.

Performance verification of precision, trueness, and accuracy of self-developed detection system in clinical chemistry

Objective To investigate the precision, trueness, and accuracy of self-developed detection system in clinical chemistry. Methods This was a methodological evaluation. Take serum creatine kinase(CK)for instance, 6 serum sampleswith different leves(on the upper or lower limit of the reference range or close to the medicine decide levels (MDLs), were collected for within-run precision(repeatability)and within-laboratory precision (intermediate precision)experiments. 5 proficiency testing(PT)samples, 5 samples assigned value by reference method, and 40 fresh-frozen serums were measured and compared with reference method for trueness verification. Drawing method evaluation decision chart, calculating total errors and sigma level evaluation experiment based on the CV, bias, and allowed total errors(TEa)were used to evaluate the accuracy performance.The precision, trueness, and accuracy were compared with the quality indicators. Results The within-run precision and within-laboratory precision were less than the highest requirement of Chinese industrial standard. The mean bias was -8.96%, didn′t reachthe required standard (5.5%). After taking corrective actions, all samples but one(-5.8%)met the required standard.Compared with the reference method, the mean bias on the MDLs was less than TEa. The performance points of the method evaluation decision chart indicated excellence performance. The total errors on MDLs were 14.2%, 10.4% and 7.6%, less than 15%. The sigma levels on MDLs were 5.9, 7.5 and 15, also achieved excellent level. Conclusions The precision, trueness, and accuracy performance of CK measured by self-developed detection system achieved excellent level of the Chinese industry standard, and the same results were found from different evaluation methods. (Chin J Lab Med, 2016, 39: 715-719) Key words: Precision; Trueness; Accuracy; Measuring system; Methodological evaluation

External quality assessment of clinical laboratory quality indicators in China in 2015

Objective To investigate an evaluation program for external quality assessment (EQA) of quality indicators (QIs) and develop a software. Methods According to GB/T 27043-2012(ISO/IEC 17043: 2010, IDT) mode 3, 28 provincial centers for clinical Laboratories were organized by National Center for Clinical Laboratories to launch an investigation onQIs in clinical laboratorywith the use of Clinet-EQA online . Participants were asked to collect data of April 2014 and report related results online. Mean, median, the 5 th, 25 th, 75 th and 95 th percentiles of defectpercentages for biochemistry, immunology, blood and body fluid and microbiology were calculated, respectively. Sigma values were also calculated.Meanwhile, 25 th of sigma value and 75 th of defect percentages were chosen as preliminary quality specifications for each QI so that laboratories can evaluate related process quality. Results Take incorrect sample type rates for example, 4 771 laboratories were involved in this study. Among four subjects, incorrect sample type rates were lowest (0.01%, 6σ) for immunology tests, followed by blood and body fluids tests (0.06%, 4.7σ) and biochemistry tests (0.06%, 4.7σ), and were highest for microbiology tests (0.33%, 4.2σ). Evaluation reports will besent back to participants so that they can understand national, provincial, and their own sigma levels well.Preliminary quality specifications of incorrect sample type for biochemistry, immunology, blood and body fluid, and microbiology tests were 0.08% (4.6σ), 0.03% (5σ), 0.09% (4.6σ) and 0.43% (4.1σ), respectively. Conclusion Clinical laboratories were advised to establish and monitor suitable QIs within laboratory and participate in QIs EQA schemes, thus they can improve their quality continuously.(Chin J Lab Med, 2016, 39: 433-437) Key words: Quality indicators; External quality assessment; Sigma metric

Multi-objective robust optimization method for the modified epoxy resin sheet molding compounds of the impeller

Abstract A kind of modified epoxy resin sheet molding compounds of the impeller has been designed. Through the test, the non-metal impeller has a better environmental aging performance, but must do the waterproof processing design. In order to improve the stability of the impeller vibration design, the influence of uncertainty factors is considered, and a multi-objective robust optimization method is proposed to reduce the weight of the impeller. Firstly, based on the fluid-structure interaction, the analysis model of the impeller vibration is constructed. Secondly, the optimal approximate model of the impeller is constructed by using the Latin hypercube and radial basis function, and the fitting and optimization accuracy of the approximate model is improved by increasing the sample points. Finally, the micro multi-objective genetic algorithm is applied to the robust optimization of approximate model, and the Monte Carlo simulation and Sobol sampling techniques are used for reliability analysis. By comparing the results of the deterministic, different sigma levels and different materials, the multi-objective optimization of the SMC molding impeller can meet the requirements of engineering stability and lightweight. And the effectiveness of the proposed multi-objective robust optimization method is verified by the error analysis. After the SMC molding and the robust optimization of the impeller, the optimized rate reached 42.5%, which greatly improved the economic benefit, and greatly reduce the vibration of the ventilation system.

IMPLEMENTASI PENERAPAN METODE SIX SIGMA PADA PROSES PERAKITAN ELEKTRO MOTOR (STUDI KASUS: PT. TATUNG ELECTRIC INDONESIA)

Tatung Electric Indonesia is a peripatetic company in manufacturing industry assembling of electro motor. So that product yielded by PT. Tatung Electric Indonesia can continue to fulfill requirement of customer, company try to improve the quality of its product by minimizing defect which during the time still happened. This defect arising caused by the existence of variation at yielded product and also that happened in the process. Six Sigma represent control technique or method to reach storey or level quality of 3.4 DPMO ( Defects Per Million Opportunities), which applied by Motorola company since year 1986. Applying strategy to be used is Define-Measure-Analyze-Improve-Control (DMAIC). This Method represent recuring step and form a make-up of quality cycle. Calculations show the company is 3.641 sigma level with DPMO 15,830. The sigma levels are on the average level of sigma industries in Indonesia (3-4 sigma). Increased levels of sigma would happen if the company immediately continuous improvement over time. Conclusion of the application of Six Sigma is the DMAIC method in the assembly process of electro motors can analyze and reduce disability that occurs that will increase the quality of products.

An Approach to Identify Six Sigma Robust Solutions of Multi/Many-Objective Engineering Design Optimization Problems

In order to be practical, solutions of engineering design optimization problems must be robust, i.e., competent and reliable in the face of uncertainties. While such uncertainties can emerge from a number of sources (imprecise variable values, errors in performance estimates, varying environmental conditions, etc.), this study focuses on problems where uncertainties emanate from the design variables. While approaches to identify robust optimal solutions of single and multi-objective optimization problems have been proposed in the past, we introduce a practical approach that is capable of solving robust optimization problems involving many objectives building on authors’ previous work. Two formulations of robustness have been considered in this paper, (a) feasibility robustness (FR), i.e., robustness against design failure and (b) feasibility and performance robustness (FPR), i.e., robustness against design failure and variation in performance. In order to solve such formulations, a decomposition based evolutionary algorithm (DBEA) relying on a generational model is proposed in this study. The algorithm is capable of identifying a set of uniformly distributed nondominated solutions with different sigma levels (feasibility and performance) simultaneously in a single run. Computational benefits offered by using polynomial chaos (PC) in conjunction with Latin hypercube sampling (LHS) for estimating expected mean and variance of the objective/constraint functions has also been studied in this paper. Last, the idea of redesign for robustness has been explored, wherein selective component(s) of an existing design are altered to improve its robustness. The performance of the strategies have been illustrated using two practical design optimization problems, namely, vehicle crash-worthiness optimization problem (VCOP) and a general aviation aircraft (GAA) product family design problem.

Diminishing Complications in Continuous Ambulatory Peritoneal Dialysis Process via Six Sigma Methodology

The aim of this paper is to investigate the complications which occurred in a dialysis polyclinic during and after CAPD process and evaluate them in terms of their root causes, severity, sigma levels and hazard scores. The data are collected from 24 patients over a 12 month period. Seventeen complications are determined. Six Sigma’s DMAIC, SIPOC table, Fishbone diagram and FMEA are employed to evaluate the overall process. Vital few CTQ factors are determined to be patient’s compliance to hygiene and presence of comorbid diseases such as diabetes, cardiovascular problems and obesity. Consequently, corrective and preventative actions are proposed for preventing the occurence of the complications.

Application of sigma metrics for the assessment of quality control in clinical chemistry laboratory in Ghana: A pilot study.

Background:Sigma metrics provide a uniquely defined scale with which we can assess the performance of a laboratory. The objective of this study was to assess the internal quality control (QC) in the clinical chemistry laboratory of the University of Cape Cost Hospital (UCC) using the six sigma metrics application.Materials and Methods:We used commercial control serum [normal (L1) and pathological (L2)] for validation of quality control. Metabolites (glucose, urea, and creatinine), lipids [triglycerides (TG), total cholesterol, high-density lipoprotein cholesterol (HDL-C)], enzymes [alkaline phosphatase (ALP), alanine aminotransferase (AST)], electrolytes (sodium, potassium, chloride) and total protein were assessed. Between-day imprecision (CVs), inaccuracy (Bias) and sigma values were calculated for each control level.Results:Apart from sodium (2.40%, 3.83%), chloride (2.52% and 2.51%) for both L1 and L2 respectively, and glucose (4.82%), cholesterol (4.86%) for L2, CVs for all other parameters (both L1 and L2) were >5%. Four parameters (HDL-C, urea, creatinine and potassium) achieved sigma levels >1 for both controls. Chloride and sodium achieved sigma levels >1 for L1 but <1 for L2. In contrast, cholesterol, total protein and AST achieved sigma levels <1 for L1 but >1 for L2. Glucose and ALP achieved a sigma level >1 for both control levels whereas TG achieved a sigma level >2 for both control levels.Conclusion:Unsatisfactory sigma levels (<3) where achieved for all parameters using both control levels, this shows instability and low consistency of results. There is the need for detailed assessment of the analytical procedures and the strengthening of the laboratory control systems in order to achieve effective six sigma levels for the laboratory.

A Comprehensive Evaluation of Eye Surgery Performance by Sigma Quality Level for Eye Care Hospitals in Turkey

Sigma Quality Levels are statistical indices that can play an important role in establishment of more reliable and robust surgical processes. This article aims to highlight the value of interpreting sigma levels as a modern means of both the efficiency and success rate of nine different type of eye surgery processes involved. Data were compiled from a comprehensive study of multiple sources—all based on medical practices—carried out in a range of eye care hospitals throughout Turkey. It is found that the eye surgery processes in Turkey operates at an average of 3.4816 sigma level. This corresponds to a DPMO of 23,725 and a yield of approximately 97.63% in 7292 surgeries. Thus, Turkish eye care hospitals have to make significant changes to drive to a 6σ level performance.

High Resolution HIRLAM Simulations of the Role of Low-Level Sea-Breeze Convergence in Initiating Deep Moist Convection in the Eastern Iberian Peninsula

We present a numerical investigation of a non-forecast sea-breeze-initiated thunderstorm that occurred unexpectedly in the eastern complex area of the Iberian Peninsula (Spain) on 7 August 2008. A high horizontal (2.5-km grid spacing) and vertical (60 sigma levels) resolution set-up of the hydrostatic HIRLAM model is used to simulate the evolution of isolated convection associated with sea breezes. The convective inhibition, convective available potential energy, vertical velocity, wind and precipitation fields are examined here in order to analyze the role of low-level sea-breeze convergence and sea-breeze front development in initiating intense convective activity (heavy rainfall, hail and gusty winds) under weakly defined synoptic disturbances. We observe that convective inhibition layers are eroded by sea-breeze frontal zones, increasing the convective available potential energy due to the enhanced vertical motion, forcing parcels to lift to the level of free convection. We show that the location of thunderstorms along the east coast of the Iberian Peninsula is partly controlled by the impact of sea-breeze fronts on modulating the diurnal spatio-temporal evolution of convective inhibition, convective available potential energy and updrafts.